Active Cell Balancing

Abstract

The integrated circuit (330) includes first, second, third, and fourth transistors (316, 314, 312, 310) and a control circuit (308). The first transistor is coupled between a first battery terminal and a first inductor terminal and has a first transistor control terminal. The second transistor is coupled between the first inductor terminal and a second battery terminal and has a second transistor control terminal. The third transistor is coupled between a third battery terminal and a second inductor terminal and has a third transistor control terminal. The third battery terminal is coupled to the second battery terminal. The fourth transistor is coupled between the second inductor terminal and a fourth battery terminal and has a fourth transistor control terminal. The control circuit has a control input and first, second, third, and fourth control outputs coupled to the first, second, third, and fourth transistor control terminals, respectively.

Description

[Technical Field]

[0001] High-voltage energy storage systems can include multiple energy storage cells, such as batteries, connected in series. The capacities of the stacked cells can vary due to internal factors (e.g., internal impedance) or external factors (e.g., temperature). This variation in capacity can result in differential charging and discharging of the cells, creating a charge imbalance across the stack and limiting the energy capacity of the system. Summary of the Invention

[0002] In one example, an integrated circuit (IC) includes first, second, third, and fourth transistors and a control circuit. The first transistor is coupled between a first battery terminal and a first inductor terminal. The first transistor has a first transistor control terminal. The second transistor is coupled between the first inductor terminal and a second battery terminal. The second transistor has a second transistor control terminal. The third transistor is coupled between the third battery terminal and the second inductor terminal. The third transistor has a third transistor control terminal. The third battery terminal is coupled to the second battery terminal. The fourth transistor is coupled between the second inductor terminal and a fourth battery terminal. The fourth transistor has a fourth transistor control terminal. The control circuit has a control input and first, second, third, and fourth control outputs. The first control output is coupled to the first transistor control terminal. The second control output is coupled to the second transistor control terminal. The third control output is coupled to the third transistor control terminal. The fourth control output is coupled to the fourth transistor control terminal.

[0003] In another example, an IC includes first, second, third, and fourth transistors and a control circuit. The first transistor is coupled between a first battery terminal and a first capacitor terminal. The first transistor has a first transistor control terminal. The second transistor is coupled between the first capacitor terminal and a second battery terminal. The second transistor has a second transistor control terminal. The third transistor is coupled between a third battery terminal and a second capacitor terminal. The third transistor has a third transistor control terminal. The third battery terminal is coupled to the second battery terminal. The fourth transistor is coupled between the second capacitor terminal and a fourth battery terminal. The fourth transistor has a fourth transistor control terminal. The control circuit has a control input and first, second, third, and fourth control outputs. The first control output is coupled to the first transistor control terminal. The second control output is coupled to the second transistor control terminal. The third control output is coupled to the third transistor control terminal. The fourth control output is coupled to the fourth transistor control terminal.

[0004] In yet another example, an IC includes first, second, third, and fourth transistors and a control circuit. The first transistor is coupled between a first battery terminal and a first switching terminal. The first transistor has a first transistor control terminal. The second transistor is coupled between the first switching terminal and a second battery terminal. The second transistor has a second transistor control terminal. The third transistor is coupled between a third battery terminal and a second switching terminal. The third transistor has a third transistor control terminal. The third battery terminal is coupled to the second battery terminal. The fourth transistor is coupled between the second switching terminal and a fourth battery terminal. The fourth transistor has a fourth transistor control terminal. A first capacitor and a first inductor are coupled between the first switching terminal and a first IC terminal. A second capacitor and a second inductor are coupled between the second switching terminal and a second IC terminal. The control circuit has a control input and first, second, third, and fourth control outputs. The first control output is coupled to the first transistor control terminal. The second control output is coupled to the second transistor control terminal. The third control output is coupled to the third transistor control terminal. The fourth control output is coupled to the fourth transistor control terminal. [Brief explanation of the drawings]

[0005] [Figure 1A] 1 illustrates an example of charge redistribution in a battery module including active cell balancing. [Figure 1B] 1 illustrates an example of charge redistribution in a battery module including active cell balancing.

[0006] [Figure 2] FIG. 1 is a block diagram of an example battery module including active cell balancing.

[0007] [Figure 3] FIG. 3 is a schematic diagram of an example of the active cell balancing circuit of FIG. 2.

[0008] [Figure 4] 4 is a graph of example signals illustrating the transfer of charge between battery cells in the active cell balancing circuit of FIG. 3.

[0009] [Figure 5] FIG. 1 is a schematic diagram of an example active cell balancing circuit with input filtering. [Figure 6] FIG. 1 is a schematic diagram of an example active cell balancing circuit with input filtering.

[0010] [Figure 7] 3 is a block diagram illustrating an example of charge transfer from one battery cell to two battery cells in the battery module of FIG. 2.

[0011] [Figure 8] 3 is a block diagram illustrating an example of multiple simultaneous charge transfers between battery cells of the battery module of FIG. 2.

[0012] [Figure 9A] 3 illustrates an example of charge transfer across six battery cells in the battery module of FIG. 2. [Figure 9B] 3 illustrates an example of charge transfer across six battery cells in the battery module of FIG. 2.

[0013] [Figure 10A] 3 illustrates an example of charge transfer across three battery cells in the battery module of FIG. 2. [Figure 10B] 3 illustrates an example of charge transfer across three battery cells in the battery module of FIG. 2.

[0014] [Figure 11A] 3 illustrates an example of simultaneous charge transfer across three battery cells and two battery cells in the battery module of FIG. 2. [Figure 11B]3 illustrates an example of simultaneous charge transfer across three battery cells and two battery cells in the battery module of FIG. 2.

[0015] [Figure 12A] 3 illustrates another example of simultaneous charge transfer across three battery cells and two battery cells in the battery module of FIG. 2. [Figure 12B] 3 illustrates another example of simultaneous charge transfer across three battery cells and two battery cells in the battery module of FIG. 2.

[0016] [Figure 13] FIG. 2 is a block diagram of an example of a portion of an active cell balancing circuit including multiple active cell balancing integrated circuits coupled in series.

[0017] [Figure 14] FIG. 1 is a schematic diagram of an active cell balancing circuit including a disconnect switch between LC circuits.

[0018] [Figure 15] FIG. 1 is a schematic diagram of an active cell balancing circuit configured for two-phase operation.

[0019] [Figure 16] 1 is a flowchart for an example method of active cell balancing.

[0020] [Figure 17] FIG. 10 is a schematic diagram of another example active cell balancing circuit.

[0021] [Figure 18A] 18 illustrates an example of simultaneous charge transfer between battery cells using the example active cell balancing circuit of FIG. 17. [Figure 18B] 18 illustrates an example of simultaneous charge transfer between battery cells using the example active cell balancing circuit of FIG. 17.

[0022] [Figure 19] FIG. 18 is a schematic diagram of an example of the active cell balancing circuit of FIG. 17 including a disconnect switch.

[0023] [Figure 20] FIG. 18 is a block diagram of an example of the active cell balancing circuit of FIG. 17 including a network of parallel capacitors.

[0024] [Figure 21] FIG. 18 is a schematic diagram of an active cell balancing circuit configured for two-phase operation based on the active cell balancing circuit of FIG. 17.

[0025] [Figure 22] FIG. 10 is a schematic diagram of another example active cell balancing circuit.

[0026] [Figure 23] FIG. 23 is a schematic diagram of an example of the active cell balancing circuit of FIG. 22 including a disconnect switch.

[0027] [Figure 24] FIG. 23 is a schematic diagram of an active cell balancing circuit configured for two-phase operation based on the active cell balancing circuit of FIG. 22.

[0028] [Figure 25] FIG. 10 is a schematic diagram of another example active cell balancing circuit.

[0029] [Figure 26] FIG. 26 is a schematic diagram of an example of the active cell balancing circuit of FIG. 25 including a disconnect switch.

[0030] [Figure 27] FIG. 26 is a schematic diagram of an active cell balancing circuit configured for two-phase operation based on the active cell balancing circuit of FIG. 25.

[0031] [Figure 28] FIG. 1 is a block diagram of a battery assembly including balancing across battery modules. DETAILED DESCRIPTION OF THE INVENTION

[0032] A high-voltage battery module includes multiple low-voltage battery cells coupled in series. The series connection of the low-voltage battery cells limits the capacity of the battery module to the capacity of the weakest low-voltage battery cell. For example, when a battery pack is discharged, the weakest cell discharges the fastest and has the lowest state of charge (SOC). When this cell's SOC reaches its lowest allowable value (e.g., the lowest value allowed by the battery manager coupled to that cell), the battery module can be disconnected and the charge stored in the other battery cells of the battery pack will not be used. Similarly, when a battery module is charged, charging can be stopped once the lowest-capacity battery cell is fully charged, leaving the higher-capacity cells partially charged.

[0033] Active cell balancing is a technique for managing the SOC of battery cells in a battery module. Active cell balancing redistributes charge across the cells of a battery module to reduce the difference in charge between the battery cells. For example, an active balancing circuit can transfer charge from a battery cell with a higher SOC to a battery cell with a lower SOC. FIGS. 1A and 1B show an example of charge redistribution in a battery module including active cell balancing. In FIG. 1A, battery cells 102 and 104 are being charged. Battery cell 102 is weaker than battery cell 104. For example, battery cell 102 charges and discharges at a faster rate than battery cell 104. During charging, active balancing circuitry transfers charge from battery cell 102 to battery cell 104, allowing both battery cell 102 and battery cell 104 to fully charge. Without active balancing, battery cell 102 may fully charge before battery cell 104, and charging may stop before battery cell 104 is fully charged. Thus, the active balancing circuitry increases the total charge stored within the battery module.

[0034] 1B , battery cells 102 and 104 are being discharged. Battery cell 102 discharges at a faster rate than battery cell 104. Active balancing circuitry transfers charge from battery cell 104 to battery cell 102 during discharge, causing both battery cell 102 and battery cell 104 to discharge equally. Without active balancing, battery cell 102 would discharge before battery cell 104, causing the battery module to be disconnected (e.g., the discharge of the battery module would be interrupted) before battery cell 104 was discharged. Thus, the active balancing circuitry increases the total charge provided by the battery module.

[0035] FIG. 2 is a block diagram of an example battery module 200 that can implement active cell balancing. The battery module 200 includes multiple battery cells. While FIG. 2 shows battery cells 202 and 204, the battery module 200 may include more than two battery cells. The battery module 200 also includes an active cell balancing circuit 206 and a battery manager circuit 208. The active cell balancing circuit 206 and the battery manager circuit 208 are coupled to the battery cells 202 and 204. The battery manager circuit 208 monitors the voltages of the battery cells 202 and 204 and the currents flowing from the battery cells 202 and 204 to determine the SOC of the battery cells 202 and 204. The battery manager circuit 208 may include measurement circuitry (e.g., an analog-to-digital converter, sampling circuitry, sensing circuitry, etc.) for measuring the voltages and currents of the battery cells 202 and 204. The battery manager circuit 208 may include a microcontroller or other computational circuitry configured to determine the SOC based on current and voltage measurements.

[0036] Battery manager circuit 208 may generate an active balancing control signal (AB_CTL) based on the SOC of battery cell 202 and battery cell 204. AB_CTL may specify that charge is transferred from battery cell 202 to battery cell 204 when the SOC of battery cell 202 is greater than the SOC of battery cell 204, or that charge is transferred from battery cell 204 to battery cell 202 when the SOC of battery cell 204 is greater than the SOC of battery cell 202. For example, AB_CTL may specify the rate and duration of charge transfer between battery cell 202 and battery cell 204 based on the SOC of battery cell 202 and battery cell 204.

[0037] Active cell balancing circuit 206 receives AB_CTL and transfers charge between battery cell 202 and battery cell 204 based on balancing parameters specified by AB_CTL (e.g., charge transfer source, charge transfer destination, charge transfer rate, and charge transfer duration, transfer start, transfer stop, and / or other parameters). As described above, battery module 200 may include two or more battery cells, and active cell balancing circuit 206 may transfer charge between any battery cells of battery module 200.

[0038] 3 is a schematic diagram of an example of an active cell balancing circuit 206 (or a portion thereof for two adjacent battery cells). FIG. 3 also shows adjacent battery cells 202 and 204 coupled to the active cell balancing circuit 206. The active cell balancing circuit 206 includes a half-bridge circuit 302, a half-bridge circuit 304, an inductor-capacitor (LC) circuit 306, and a control circuit 308. The half-bridge circuit 302 is coupled in parallel with the battery cell 202 and includes a first battery terminal coupled to a first terminal of the battery cell 202 and a second battery terminal coupled to a second terminal of the battery cell 202. Similarly, the half-bridge circuit 304 is coupled in parallel with the battery cell 204 and includes a first battery terminal coupled to a first terminal of the battery cell 204 and a second battery terminal coupled to a second terminal of the battery cell 204.

[0039] Each half-bridge circuit includes a pair of transistors, which may be n-channel field-effect transistors (NFETs). Half-bridge circuit 302 includes transistors 310 and 312. A first terminal (e.g., a source) of transistor 310 is coupled to the second battery terminal, and a second terminal (e.g., a drain) of transistor 310 is coupled to a switch node 332. Capacitor 322 represents the drain-source capacitance of transistor 310. A first terminal (e.g., a source) of transistor 312 is coupled to switch node 332, and a second terminal (e.g., a drain) of transistor 312 is coupled to the first battery terminal. Capacitor 324 represents the drain-source capacitance of transistor 312.

[0040] The half-bridge circuit 304 includes transistors 314 and 316 and a switch node 334. A first terminal (e.g., a source) of the transistor 314 is coupled to a first terminal of the battery cell 204, and a second terminal (e.g., a drain) of the transistor 314 is coupled to the switch node 334. A capacitor 326 represents the drain-to-source capacitance of the transistor 314. A first terminal (e.g., a source) of the transistor 316 is coupled to the switch node 334, and a second terminal (e.g., a drain) of the transistor 316 is coupled to the second terminal of the battery cell 204. A capacitor 328 represents the drain-to-source capacitance of the transistor 316.

[0041] LC circuit 306 is coupled between switch node 332 and switch node 334. LC circuit 306 includes an inductor 318 and a capacitor 320 coupled in series. Capacitor 320 capacitively couples half-bridge circuit 302 and half-bridge circuit 304. The capacitance of capacitor 320 and the inductance of inductor 318 may be relatively small. For example, in some implementations of active cell balancing circuit 206, the inductance of inductor 318 may be 50 nanohenries, and the capacitance of capacitor 320 may be 3 microfarads. The voltage across transistor 310, transistor 312, transistor 314, transistor 316, inductor 318, or capacitor 320 may be limited to about the voltage of a single battery cell. Therefore, the voltage ratings of these components may be relatively low.

[0042] The control circuit 308 receives the AB_CTL provided by the battery manager circuit 208 (FIG. 2) and generates driver signals that control the transistors 310, 312, 314, and 316. The control circuit 308 generates the driver signals C1, TIFF2026500953000002.tif913, C2, and TIFF2026500953000003.tif913 and provides a driver signal at the output of control circuit 308 that is coupled to the control inputs (eg, gates) of transistors 310 , 312 , 314 , and 316 . TIFF2026500953000004.tif913 is C1 and TIFF2026500953000005.tif913, and C2 and TIFF2026500953000006.tif913 is C1 and By controlling the switching of transistors 310, 312, 314, and 316 using a selected phase shift between the driver signals provided to half-bridge circuit 302 and half-bridge circuit 304, active cell balancing circuit 206 can transfer charge from battery cell 202 to battery cell 204 or from battery cell 204 to battery cell 202. In some examples, driver signals C1, C2, C3, C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, C16, C17, C18, C19, C20, C21, C22, C23, C24, C25, C26, C27, C28, C29, C30, C31, C32, C33, C34, C35, C36, C37, C38, C39, C40, C41, C42, C43, C44, C45, C46, ​​C47, C48, C49, C50, C51, C52, C53, C54, C55, C56, C57, C58, C59, C60, C61, C62, C63, C64, C65, C66, C67, C68, C70, C71, C72, C73, C74, C75, C76, C77, C78, ​​C79, C80, C81, C82, C83, C84, C85, C90, C91, C92, C93, C94, C95, C96, C97, C98, C99, C100, C111, C121, C131, C132, C141, C152, C162, C TIFF2026500953000008.tif913, C2, and TIFF2026500953000009.tif913 may each have a 50% duty cycle. In some examples, when the imbalance between the cell voltages is large, the duty cycle may deviate from 50% to improve efficiency. In some examples, when the voltage imbalance between the battery cells is extreme, discontinuous conduction mode (DCM) operation may be implemented to reduce losses.

[0043] In some examples of the active cell balancing circuit 206, the control circuit 308 may be distributed across the half-bridge circuit. For example, the control signals C1 and C2 may be The portion of the control circuit 308 that generates TIFF2026500953000010.tif913 may be provided in a first sub-circuit comprising the half-bridge circuit 302, with the control signals C2 and The portion of the control circuit 308 that generates TIFF2026500953000011.tif913 may be provided in a second sub-circuit that comprises the half-bridge circuit 304. With the control circuit 308 distributed across the half-bridge circuit, each portion of the control circuit 308 may receive transfer parameters such as source, sink, and current via AB_CTL and may adjust the phase of the generated control signal to maintain a specified current.

[0044] The half-bridge circuit 302, the half-bridge circuit 304, and the control circuit 308 may be integrated into an integrated circuit 330. Some examples of the integrated circuit 330 may also include an inductor 318. Some examples of the integrated circuit 330 may include any number of series-connected half-bridge circuits (e.g., the half-bridge circuit 302, the half-bridge circuit 304), with the control circuit 308 configured to control these half-bridge circuits.

[0045] 4 is a graph of signals in the active cell balancing circuit 206 illustrating the transfer of charge from the battery cell 202 to the battery cell 204 during a switching cycle of the half-bridge circuits 302 and 304. In interval 402, the control circuit 308 is in a first state TIFF2026500953000012.tif913 and TIFF2026500953000013.tif913 to turn on transistors 310 and 314, and C1 and C2 in a second state to turn off transistors 312 and 316. The voltage across transistors 310 and 314 is zero or near zero. The current i B,AC1 is negative.

[0046] During interval 404, control circuit 308 TIFF2026500953000014.tif913 to turn on transistor 314 and set the second state TIFF2026500953000015.tif913, C1, and C2( TIFF2026500953000016.tif913 transitions from the second state to the first state) to turn off transistors 310, 312, and 316. Transistor 312 can be turned off using zero voltage switching. TIFF2026500953000017.tif1116 increases in size.

[0047] In interval 406, after the voltage across transistor 310 rises to a selected value, control circuit 308 may provide C1 in a first state to turn on transistor 312. Current i B,AC1 flows through transistor 312 due to the battery voltage across inductor 318. In this configuration, transistors 310 and 316 are turned off, and transistors 312 and 314 are turned on, providing a path for current to flow. Capacitor 320 may provide capacitive isolation between adjacent battery cells, as described above, and may have a relatively low voltage tolerance (e.g., 5 volts). The voltage across capacitor 320 may be the average of voltage v1 across battery cell 202 and voltage v2 across battery cell 204. Because the voltage across inductor 318 is opposite in polarity to the voltage across capacitor 320 (the total voltage is zero because switch nodes 334 and 332 are both shorted by transistors 314 and 312), the voltage across inductor 318 (i B,AC1 ) increases (rises), and the ramp rate may be determined by the inductance of inductor 318. The duration of interval 406 may determine the amount of increase and amount of charge transfer before the current stops increasing.

[0048] During interval 408, after the current through inductor 318 has increased to a selected value, control circuit 308 switches to the second state. TIFF2026500953000018.tif913 to turn off transistor 314. In this configuration, transistors 310, 314, and 316 are off and transistor 312 is on. The voltage across transistor 314 TIFF2026500953000019.tif918 will grow.

[0049] During interval 410, after the voltage across transistor 314 has increased to a selected value, control circuit 308 may supply C2 in a second state to turn on transistor 316 using zero voltage switching. In this configuration, transistors 310 and 314 are off and transistors 312 and 316 are on. The voltage across inductor 318 is zero, and inductor (i B,AC1 ) remains at (or near) a selected value. During interval 410 (the power transfer interval), charge is transferred from LC circuit 306 to battery cell 204. Thus, the charge transferred from battery cell 202 to LC circuit 306 is transferred to battery cell 204.

[0050] During interval 412, control circuit 308 may provide C1 in the second state to turn off transistor 312. The voltage across transistor 310 TIFF2026500953000020.tif918 will be degraded.

[0051] In interval 414, after the voltage across transistor 310 has decreased to a selected value, control circuit 308 selects the first state of TIFF2026500953000021.tif913 may be supplied to turn on transistor 310 using zero voltage switching. B,AC1 decreases and becomes negative.

[0052] During interval 416, when the current through inductor 318 drops to a selected value, control circuit 308 may provide C2 in a second state to turn off transistor 316. TIFF2026500953000022.tif1117 will be degraded.

[0053] During interval 418, when the voltage across transistor 314 drops to a selected value, control circuit 308 switches the first state TIFF2026500953000023.tif913 may be provided to turn on transistor 314 using zero voltage switching. In interval 418, active cell balancing circuit 206 is in the same state as in interval 402 to perform a continuous power transfer cycle.

[0054] 4, inductor 318 and capacitor 320 form a resonant circuit to support soft switching, allowing switch nodes (332 and 334) to commutate without discharging capacitors 322, 324, 326, and 328. This arrangement improves switching speed, allowing half-bridge circuits 302 and 304 to operate at a faster switching frequency, thereby reducing the size of the devices in half-bridge circuits 302 and 304. Increasing the switching frequency reduces the time that capacitor 320 blocks DC voltage, allowing the size of capacitor 320 to be reduced.

[0055] FIG. 4 illustrates the transfer of charge from battery cell 202 to battery cell 204, with signals C1 and C2 in FIG. The timing of TIFF2026500953000024.tif913 and signals C2 and C3 in Fig. 4 By interchanging the timing of TIFF2026500953000025.tif913, charge transfer from battery cell 204 to battery cell 202 can be provided.

[0056] 5 is a high-level diagram of an example of an active cell balancing circuit 206 including input filtering. In the example of FIG. 5, the active cell balancing circuit 206 includes half-bridge circuits 302, 304, 502, and 504, and LC circuits 306, 520, and 522. The active cell balancing circuit 206 may include any number of half-bridge circuits, with each half-bridge circuit coupled to an adjacent half-bridge circuit by an LC circuit (e.g., an example of LC circuit 306). All half-bridge circuits may be similar or identical, and all LC circuits may be similar or identical. The half-bridge circuits 302, 304, 502, and 504 are connected to each other by a LC circuit (e.g., an example of LC circuit 306). interconnect 5. The power supply 201 is coupled to the battery cells 202, 204, 508, and 510, respectively, via conductors represented as

[0057] Active cell balancing circuit 206 also includes an input filter circuit 506. Input filter circuit 506 includes capacitors 512, 514, 516, and 518. Capacitor 512 is coupled across the battery terminals of half-bridge circuit 504. Capacitor 514 is coupled across the battery terminals of half-bridge circuit 502. Capacitor 516 is coupled across the battery terminals of half-bridge circuit 304. Capacitor 518 is coupled across the battery terminals of half-bridge circuit 302. Generally, input filter circuit 506 includes capacitors coupled across the battery terminals of each half-bridge circuit of active cell balancing circuit 206. Each of the capacitors in input filter circuit 506 blocks the DC voltage of a single battery cell. When transferring charge between two battery cells (e.g., transferring charge from battery cell 202 to battery cell 510), the equivalent capacitance of input filter circuit 506 is C / (j-1), where C is the capacitance of each capacitor in input filter circuit 506 and j is the number of capacitors in input filter circuit 506 that are coupled in series between the two battery cells (e.g., when transferring charge from battery cell 202 to 508, j=3).

[0058] FIG. 6 is a schematic level diagram of an example of an active cell balancing circuit 206 similar to FIG. 5 but including different input filtering. In FIG. 6, active cell balancing circuit 206 includes an input filter circuit 606 instead of input filter circuit 506. Input filter circuit 606 includes capacitors 612, 614, 616, and 618. Capacitor 612 is coupled across battery cells 510, 508, 204, and 202. Capacitor 614 is coupled across battery cells 508, 204, and 202. Capacitor 616 is coupled across battery cells 204 and 202. Capacitor 618 is coupled across battery cell 202. Each of the capacitors blocks the DC voltage of the series-connected battery to which it is connected. When transferring charge between two battery cells, the equivalent capacitance of input filter circuit 606 is C (the capacitance of one capacitor of input filter circuit 606). Thus, input filter circuit 606 may reduce the AC signal path capacitance between battery cells compared to input filter circuit 506.

[0059] In the example of the active cell balancing circuit 206, the current transferred from one battery cell to another can be modeled as follows: TIFF2026500953000026.tif1767Where V is the battery voltage, L is the inductance of an inductor such as inductor 318; φ is the phase shift between the driver signals driving the half-bridge circuits (e.g., C1 and C1), fsw is the switching frequency.

[0060] Thus, the phase shift generated by the control circuit 308 to provide a selected charge transfer between the battery cells may be determined as follows: TIFF2026500953000027.tif2085

[0061] 7 is a block diagram illustrating an example of charge transfer from one battery cell to two battery cells in battery module 200. In FIG. 7, battery module 200 includes battery cells 202, 204, and 508 coupled to half-bridge circuits 302, 304, and 502, respectively, and LC circuits 306 and 520 coupled to the half-bridge circuits. Half-bridge circuit 502 may be the same as half-bridge circuit 302, and LC circuit 520 may be the same as LC circuit 306. In the example of FIG. 7, charge may be transferred simultaneously from battery cell 202 to battery cell 204 and battery cell 508. Driver signals provided to half-bridge circuits 302, 304, and 502 direct 70% of the charge provided by battery cell 202 to battery cell 204 and 30% of the charge provided by battery cell 202 to battery cell 508. The amount of charge directed to each of battery cells 204 and 508 is determined by the phase of driver signals C1, C2, and C3 provided by control circuit 308 to half-bridge circuits 302, 304, and 502. Control circuit 308 may determine the phase shift to apply to C2 (relative to C1) as follows: TIFF2026500953000028.tif20103 where, I 1A specifies 1 ampere of total current flowing from battery cell 202 to battery cell 204 and battery cell 508.

[0062] Control circuitry 308 may determine the phase shift to apply to C3 (relative to C2) as follows: TIFF2026500953000029.tif19102 where, I 0.3A identifies a current of 0.3 amps flowing from battery cell 202 to battery cell 508. In some examples, control circuit 308 may be coupled to a current sensor that senses the amount of current flowing between the two half-bridges. Control circuit 308 may set a phase shift for the switching of the two half-bridges based on the sensed current to provide closed-loop control of the current.

[0063] 8 is a block diagram illustrating examples of charge transfers between battery cells of battery module 200. In FIG. 8, battery module 200 includes battery cells 202, 204, 802, 804, 806, 818, 820, 822, and 824, half-bridge circuits 302, 304, 808, 810, 812, 826, 828, 830, and 832 coupled to the battery cells, and LC circuits 306, 814, 816, 834, 836, and 838 coupled to the half-bridge circuits. Half-bridge circuits 808, 810, 812, 826, 828, 830, and 832 may be the same as half-bridge circuit 302, and LC circuits 814, 816, 834, 836, and 838 may be the same as LC circuit 306. Battery module 200 may also include batteries, half-bridge circuits, and LC circuits, not shown. In FIG. 8, charge is transferred from battery cell 202 to battery cell 204, from battery cell 802 to battery cell 806, and from battery cell 824 to battery cell 818. Multiple charge transfers may occur simultaneously. Control circuit 308 controls the transfers by setting the phase of the driver signals provided to the half-bridge circuits. In FIG. 8, the driver signal provided to half-bridge circuit 304 is shifted right (delayed) relative to the driver signal provided to half-bridge circuit 302 to transfer charge from battery cell 202 to battery cell 204.

[0064] In transferring charge to battery cell 806, the driver signal provided to half bridge circuit 810 is right shifted (delayed) relative to the driver signal provided to half bridge circuit 808. The driver signal provided to half bridge circuit 812 is right shifted (delayed) relative to the driver signal provided to half bridge circuit 810 to transfer charge from battery cell 802 to battery cell 806.

[0065] In transferring charge to battery cell 818, the driver signal provided to half-bridge circuit 830 is right shifted (delayed) relative to the driver signal provided to half-bridge circuit 832. The driver signal provided to half-bridge circuit 828 is right shifted (delayed) relative to the driver signal provided to half-bridge circuit 830. The driver signal provided to half-bridge circuit 826 is right shifted (delayed) relative to the driver signal provided to half-bridge circuit 828 to transfer charge from battery cell 824 to battery cell 818.

[0066] 9A and 9B illustrate an example of charge transfer across six battery cells in a battery module 200. In FIG. 9A, the battery module 200 includes battery cells 202, 204, 906, 908, 910, and 912 coupled to half-bridge circuits 302, 304, 914, 916, 918, and 920, respectively. LC circuits 306, 922, 924, 926, and 928 are coupled to the half-bridge circuits. Half-bridge circuits 914, 916, 918, and 920 may be the same as half-bridge circuit 302, and LC circuits 922, 924, 926, and 928 may be the same as LC circuit 306. In FIG. 9A, charge is transferred from battery cell 202 to battery cell 912. 9B illustrates the switching in half-bridge circuits 302, 304, 914, 916, 918, and 920 (e.g., driver signals provided by control circuit 308 to half-bridge circuits 302, 304, 914, 916, 918, and 920). The switching in half-bridge circuit 304 is delayed (phase shifted) relative to the switching in half-bridge circuit 302. The switching in half-bridge circuit 914 is delayed (phase shifted) relative to the switching in half-bridge circuit 304. The switching in half-bridge circuit 916 is delayed (phase shifted) relative to the switching in half-bridge circuit 914. The switching in half-bridge circuit 918 is delayed (phase shifted) relative to the switching in half-bridge circuit 916. The switching in half-bridge circuit 920 is delayed (phase shifted) relative to the switching in half-bridge circuit 918. An equal phase shift may be applied across the half-bridge circuits. For example, the phase shift between switching between half-bridge circuit 302 and half-bridge circuit 304 is the same as the phase shift between switching between half-bridge circuit 304 and half-bridge circuit 914, half-bridge circuit 914 and half-bridge circuit 916, half-bridge circuit 916 and half-bridge circuit 918, and half-bridge circuit 918 and half-bridge circuit 920.

[0067] This switching arrangement allows charge to be transferred from battery cell 202 to battery cell 204, from battery cell 204 to battery cell 906, from battery cell 906 to battery cell 908, from battery cell 908 to battery cell 910, and from battery cell 910 to battery cell 912, resulting in a net charge transfer from battery cell 202 to battery cell 912. Multiple charge transfers can occur simultaneously. This switching arrangement also reduces the total inductance between the pair of half-bridge circuits between which charge transfers occur. For example, when charge is transferred from battery cell 202 to battery cell 204 via half-bridge circuits 302 and 304, current flows through LC circuit 306 (and inductor 318) but not through other LC circuits. When charge is transferred from battery cell 910 to battery cell 912, current flows through LC circuit 928 (and the inductor corresponding to inductor 318) but not through any other LC circuits. By limiting the total inductance, the ramp rate of the inductor current between the switching phase shifts between the half-bridge pair (e.g., within interval 406 in FIG. 4 ) may increase, which may also increase the duration of the power transfer interval 410 within each cycle and improve the efficiency of charge transfer. On the other hand, if the intervening half bridges between half bridges 302 and 920 are not switched, the current flowing from half bridge 302 to half bridge 920 may encounter the combined inductance of LC circuits 306, 922, 924, 926, and 928. Increasing the total inductance may slow the ramp rate of the inductor current between the switching phase shifts between half bridges 302 and 920, thereby shortening the duration of the power transfer interval 410 within each cycle and reducing the efficiency of charge transfer. Because the ramp rate of the inductor current is slowed, the switching frequency may also be reduced and lengthened, which may increase the size of the capacitor in the LC circuit between the half-bridge circuits.

[0068] 10A and 10B illustrate an example of charge transfer across three battery cells in battery module 200. In FIG. 10A, battery module 200 is the same as that shown in FIG. 9A. In FIG. 10A, charge is transferred from battery cell 202 to battery cell 906. FIG. 10B illustrates switching in half-bridge circuits 302, 304, 914, 916, 918, and 920 (e.g., driver signals provided to half-bridge circuits 302, 304, 914, 916, 918, and 920 by control circuit 308). Switching in half-bridge circuit 304 is delayed (phase-shifted) relative to switching in half-bridge circuit 302. Switching in half-bridge circuit 914 is delayed (phase-shifted) relative to switching in half-bridge circuit 304. Switching in half-bridge circuits 916, 918, and 920 is in phase with switching in half-bridge circuit 914. With this switching, charge is transferred from battery cell 202 to battery cell 906 and little or no charge is transferred from battery cell 202 to battery cells 204, 908, 910, or 912.

[0069] 11A and 11B illustrate an example of charge transfer across three and two battery cells in battery module 200. In FIG. 11A, battery module 200 is the same as that shown in FIG. 9A. In FIG. 11A, charge is transferred from battery cell 202 to battery cell 906 and from battery cell 910 to battery cell 908. Multiple charge transfers can occur simultaneously. FIG. 11B illustrates switching in half-bridge circuits 302, 304, 914, 916, 918, and 920 (e.g., driver signals provided to half-bridge circuits 302, 304, 914, 916, 918, and 920 by control circuit 308). Switching in half-bridge circuit 304 is delayed (phase-shifted) relative to switching in half-bridge circuit 302. Switching in half-bridge circuit 914 is delayed (phase-shifted) relative to switching in half-bridge circuit 304. The switching in half-bridge circuit 916 is in phase with the switching in half-bridge circuit 914. The switching in half-bridge circuits 918 and 920 is in phase with the switching in half-bridge circuit 304. With this switching, charge is transferred from battery cell 202 to battery cell 906, and little or no charge is transferred from battery cell 202 to battery cell 204. Charge is also transferred from battery cell 910 to battery cell 908, but no charge is transferred to or from battery cell 912.

[0070] 12A and 12B illustrate another example of charge transfer across three and two battery cells in a battery module 200. In FIG. 12A, the battery module 200 is the same as that shown in FIG. 9A. In FIG. 12A, charge is transferred from battery cell 202 to battery cell 906 and from battery cell 908 to battery cell 910. Multiple charge transfers can occur simultaneously. FIG. 12B illustrates switching in half-bridge circuits 302, 304, 914, 916, 918, and 920 (e.g., driver signals provided to half-bridge circuits 302, 304, 914, 916, 918, and 920 by control circuit 308). The switching in half-bridge circuit 304 is delayed (phase-shifted) relative to the switching in half-bridge circuit 302. The switching in half-bridge circuit 914 is delayed (phase-shifted) relative to the switching in half-bridge circuit 304. The switching in half-bridge circuit 916 is in phase with the switching in half-bridge circuit 914. The switching in half-bridge circuits 918 and 920 is in phase and delayed (phase shifted) with respect to the switching in half-bridge circuit 916. With this switching, charge is transferred from battery cell 202 to 906, and little or no charge is transferred from battery cell 202 to battery cell 204. Charge is also transferred from battery cell 908 to battery cell 910, but no charge is transferred to or from battery cell 912.

[0071] FIG. 13 is a block diagram of a portion of an example battery module 200. In FIG. 13, the battery module 200 includes multiple integrated circuits 330. Each integrated circuit 330 may include multiple half-bridge circuits (e.g., half-bridge circuits 302, 304, etc.). Each half-bridge circuit is coupled to a battery cell (e.g., battery cells 202, 204, etc.) and an LC circuit (e.g., an example of an LC circuit 306). Each integrated circuit 330 may provide a synchronization signal (labeled SYNC in FIG. 13) to the subsequent integrated circuit 330. The synchronization signal enables synchronization of the timing (phase) of the driver signals generated by the control circuit 308 of each integrated circuit 330. The battery manager circuit 208 may be coupled to each of the battery cells and to each integrated circuit 330 for measuring battery cell parameters and communicating balancing parameters. Thus, the active cell balancing circuit 206 may set the phase of the driver signals generated in each of the integrated circuits 330 to transfer charge between batteries coupled to different instances of the integrated circuits 330.

[0072] FIG. 14 is a schematic diagram of an example active cell balancing circuit including a disconnect switch coupled across an LC circuit. In FIG. 14, the active cell balancing circuit includes half-bridge circuits 1400 and 1402 and a transistor 1404. In some examples, the active cell balancing circuit may include two or more half-bridge circuits. Half-bridge circuits 1400 and 1402 may be the same as half-bridge circuit 302. LC circuits 1406 and 1408 may be the same as LC circuit 306. Transistor 1404 is coupled between a switch node of half-bridge circuit 1400 and a capacitor terminal of the active cell balancing circuit. For example, a first current terminal (e.g., a source) of transistor 1404 is coupled to a first capacitor terminal of the active cell balancing circuit, and a second current terminal (e.g., a drain) of transistor 1404 is coupled to a switch node of half-bridge circuit 1400. An LC circuit 1408 is coupled between transistor 1404 and the switch node of half-bridge circuit 1402. An LC circuit 1406 is coupled to transistor 1404 and the switch node of half-bridge circuit 1400. The active cell balancing circuit may include any number of instances of transistor 1404. For example, the active cell balancing circuit may include an instance of transistor 1404 coupled to the switch node of each half-bridge circuit, or an instance of transistor 1404 coupled to the switch node of every other half-bridge circuit, or every fourth half-bridge circuit, or every tenth half-bridge circuit, etc. These half-bridge circuits, transistor 1404, and control circuit 308 may be included in integrated circuit 330.

[0073] Transistor 1404 can be configured as a unidirectional switch or a bidirectional switch. In some examples, transistor 1404 reduces the number of half-bridge circuits that are switched during charge transfer. For example, in FIG. 10A , half-bridge circuits 916, 918, and 920 are switched even when no charge is being transferred to battery cells 908, 910, and 912. In one example of an active balancing circuit that includes transistor 1404 between half-bridge circuits 914 and 916, transistor 1404 can be turned off and half-bridge circuits 916, 918, and 920 do not need to be switched. Control circuit 308 includes an output coupled to the control terminal of transistor 1404. Control circuit 308 generates a control signal C for controlling the on / off of transistor 1404 based on AB_CTL. D to provide.

[0074] In some examples, transistor 1404 may be coupled between the switching node of the half-bridge circuit and the LC circuit. For example, a first current terminal of transistor 1404 may be coupled to the switching node of half-bridge circuit 1400, and a second current terminal of transistor 1404 may be coupled to both LC circuits 1406 and 1408 (e.g., the second current terminal of transistor 1404 may be coupled to the junction of LC circuits 1406 and 1408). In such examples, an instance of transistor 1404 may be coupled to the switching node of each half-bridge circuit. To allow charge transfer between the half-bridge circuits on either side of the selected half-bridge circuit while the selected half-bridge circuit remains idle (unswitched), transistor 1404 of the selected half-bridge circuit may be turned off, and the transistor of the selected half-bridge circuit may be turned off.

[0075] 15 is a schematic diagram of an example active cell balancing circuit configured for two-phase operation. In the active cell balancing circuit of FIG. 15 , half-bridge circuits 302 and 304 and LC circuits 306 and 1508 are configured to operate in a first phase (e.g., to transfer charge between battery cells 202 and 204). Half-bridge circuits 1502 and 1504 and LC circuits 1506 and 1508 are configured to operate in a second phase (e.g., to transfer charge between battery cells 202 and 204). Half-bridge circuits 302 and 1502 are coupled in parallel to battery cell 202. Half-bridge circuits 304 and 1504 are coupled in parallel to battery cell 204. The active cell balancing circuit may include any number of half-bridge circuits coupled in series in each phase. Half-bridge circuits 1502 and 1504 may be the same as half-bridge circuit 302 , and LC circuits 1506 , 1508 , and 1510 may be the same as LC circuit 306 .

[0076] The control circuit 308 is coupled to the half-bridge circuits 302, 304, 1502, and 1504 and provides driver signals C1, C2, C3, C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, C16, C17, C18, C19, C20, C21, C22, C23, C24, C25, C26, C27, C28, C29, C29, C30, C31, C32, C33, C34, C35, C36, C37, C38, C39, C40, C41, C42, C43, C44, C45, C46, ​​C47, C48, C49, C50, C51, C52, C53, C54, C55 TIFF2026500953000030.tif913, C2, TIFF2026500953000031.tif813,C1', TIFF2026500953000032.tif1114, C2', and The switching of half-bridge circuits 1502 and 1504 may be 180 degrees out of phase with the switching of half-bridge circuits 302 and 304, respectively. The half-bridge circuits and control circuit 308 may be incorporated into an integrated circuit 330.

[0077] Two-phase operation reduces current stress on the transistors in the half-bridge circuit and reduces current ripple, while at the same time increasing the circuit area by little or nothing compared to a single-phase implementation. Although not shown in FIG. 15, the active balancing circuit may include input filter circuit 506 or input filter circuit 606. Because the two phases operate 180 degrees out of phase, two-phase operation can reduce the AC component in the current through the input filter.

[0078] 16 is a flowchart of an example method 1600 of active cell balancing. While shown sequentially for convenience, at least some of the actions shown may be performed in a different order and / or in parallel. Also, some implementations may perform only a portion of the actions shown. The operations of method 1600 may be performed by an example of active cell balancing circuit 206.

[0079] In block 1602, by turning on transistor 310 and transistor 314, capacitor 320 and inductor 318 are connected between a first terminal (e.g., a positive terminal) of battery cell 202 and a second terminal (e.g., a negative terminal) of battery cell 202. By connecting capacitor 320 and inductor 318 between the first battery terminal and the second battery terminal of battery cell 202, a first voltage (e.g., voltage v1 of battery cell 202) is provided across capacitor 320. A capacitor terminal of capacitor 320 is coupled to the first terminal of battery cell 202 through transistor 314, and an inductor terminal of inductor 318 is coupled to the second terminal of battery cell 202 through transistor 310. The operations of block 1602 may be performed during interval 402 of FIG. 4 .

[0080] In block 1604, the inductor terminal is disconnected from the second battery terminal of the battery cell 202 by turning off the transistor 310. The operations of block 1604 may be performed during the interval 404 of FIG.

[0081] In block 1606, the inductor terminal is connected to the first battery terminal of the battery cell 202 by turning on the transistor 312. The voltage across the capacitor 320 is provided across the inductor 318. The operations of block 1606 may be performed during the interval 406 of FIG.

[0082] In block 1608, the capacitor terminal is disconnected from the first battery terminal of the battery cell 202 by turning off the transistor 314. The operations of block 1608 may be performed during the interval 408 of FIG.

[0083] In block 1610, the capacitor terminal is connected to a battery terminal (e.g., a positive terminal) of the battery cell 204 by turning on the transistor 316. Connecting the capacitor terminal to the third battery terminal of the battery cell 204 transfers charge from the capacitor 320 (e.g., the charge from the battery cell 202 that was stored in the capacitor 320 in block 1602) to the battery cell 204. The charge transfer rate may be based on the first voltage and the inductance of the inductor 318. The operation of block 1610 may be performed during interval 410 of FIG. 4.

[0084] In method 1600, control circuit 308 may determine a delay interval and apply the delay interval to the connection of the inductor terminal to the first battery terminal relative to the connection of the capacitor terminal to the third battery terminal. The delay interval may be determined based on a target amount of charge to be transferred from battery cell 202 to battery cell 204.

[0085] FIG. 17 is a schematic diagram of another active cell balancing circuit 1706. The active cell balancing circuit 1706 includes half-bridge circuits 302, 304, 502, and 504 coupled to battery cells 202, 204, 508, and 510, respectively. An example of the active cell balancing circuit 1706 may include any number of half-bridge circuits coupled in series. The half-bridge circuits may be included in the integrated circuit 330. The active cell balancing circuit 1706 is similar to the active cell balancing circuit 206, except that the arrangement of the inductors in the active cell balancing circuit 1706 is different from that of the active cell balancing circuit 206. In the active cell balancing circuit 206, the inductors and capacitors are coupled in series. In the active cell balancing circuit 1706, the capacitors are in series, and the inductors are coupled between the switch nodes of the half-bridge circuits and the series capacitors. Thus, in the active cell balancing circuit 1706, the path between two half-bridge circuits separated by any number of battery cells and half-bridge circuits may include only a capacitor and two inductors. Such an arrangement may reduce losses that may occur through the inductors and may facilitate power transfer over long distances (e.g., between battery cells separated by a large number of battery cells). In some examples, the inductors used in the active cell balancing circuit 1706 may have half the inductance of the inductors used in the active cell balancing circuit 206. Although not shown in FIG. 17 , the active cell balancing circuit 1706 may also include the input filter circuit 506 or the input filter circuit 606.

[0086] An inductor is coupled to the switch node of each half-bridge circuit. A first terminal of inductor 1702 is coupled to the switch node of half-bridge circuit 302. A first terminal of inductor 1705 is coupled to the switch node of half-bridge circuit 304. A first terminal of inductor 1710 is coupled to the switch node of half-bridge circuit 502. A first terminal of inductor 1714 is coupled to the switch node of half-bridge circuit 504. A capacitor is coupled between the inductors coupled to the switch node of the subsequent half-bridge circuit. Capacitor 1704 is coupled between the second terminal of inductor 1702 and the second terminal of inductor 1705. Capacitor 1708 is coupled between the second terminal of inductor 1705 and the second terminal of inductor 1710. Capacitor 1712 is coupled between the second terminal of inductor 1710 and the second terminal of another inductor (e.g., inductor 1714).

[0087] The control circuit 308 is coupled to the half-bridge circuits 302, 304, 502, and 504. The control circuit 308 generates driver signals that control switching in the half-bridge circuits. The half-bridge switching for transferring charge between two batteries may be the same as that described in FIG. 4. In the active cell balancing circuit 206 (e.g., as shown in FIG. 5), when charge is transferred between any two battery cells, the control circuit 308 switches all of the half-bridge circuits (e.g., see FIGS. 10A and 10B). In the active cell balancing circuit 1706, because only two inductors are connected in series between a pair of half-bridge circuits, only the half-bridge circuits transferring charge are switched, and the intervening half-bridges between the pair of half-bridges do not need to be switched. For example, to transfer charge from battery cell 202 to battery cell 508, control circuit 308 switches half-bridge circuit 302 and half-bridge circuit 502 according to the timing of FIG. 4, while half-bridge circuit 304, half-bridge circuit 504, and any other half-bridge circuits in active cell balancing circuit 1706 are not switched. As described in FIG. 9A, switching intervening half-bridges (and, when switched, equally phase-shifting them) may reduce the total inductance along the current path between pairs of half-bridges involved in the charge transfer. Such an arrangement may be eliminated by limiting the number of inductors between any pair of half-bridges in active cell balancing circuit 1706 to two.

[0088] 18A and 18B illustrate an example of charge transfer between different pairs of battery cells in a battery module using an example active cell balancing circuit 1706. In FIG. 18A, the battery module includes battery cells 202, 204, 906, 908, 910, and 912 coupled to half-bridge circuits 302, 304, 914, 916, 918, and 920. Half-bridge circuits 914, 916, 918, and 920 may be the same as half-bridge circuit 302. One of inductors 1702, 1705, 1710, 1716, 1720, or 1714 is coupled to the switch node of each half-bridge circuit, and one of capacitors 1704, 1708, 1712, 1718, or 1722 is coupled between adjacent inductors. In Figure 18A, charge is transferred from battery cell 204 to battery cell 202 and from battery cell 910 to battery cell 912. Multiple charge transfers can occur simultaneously. Figure 18B illustrates switching in half-bridge circuits 302, 304, 918, and 920 (e.g., driver signals provided by control circuit 308 to half-bridge circuits 302, 304, 914, 916, 918, and 920). Switching in half-bridge circuit 302 is delayed (phase-shifted) relative to switching in half-bridge circuit 304. Switching in half-bridge circuit 920 is delayed (phase-shifted) relative to switching in half-bridge circuit 918. Switching in half-bridge circuit 918 can be in phase with switching in half-bridge circuit 304. Half-bridge circuits 914 and 916 are idle (not switching). Using this switching, charge is transferred from battery cell 204 to battery cell 202 and from battery cell 910 to battery cell 912. No charge is transferred to or from battery cell 906 or battery cell 908. In some examples, the half-bridge circuit coupled to the sink battery cell is switched in phase, and the phase shift applied to the half-bridge circuit coupled to the source battery cell can be adjusted to transfer charge.

[0089] In the active cell balancing circuit 1706, increasing the number of capacitors coupled in series between the source half-bridge circuit and the sink half-bridge circuit reduces the capacitance and increases the resonant frequency of the LC network formed by the inductors and capacitors. In some examples, the control circuit 308 can switch the half-bridge circuit at a fixed switching frequency. The active cell balancing circuit 1706 transfers power when the switching frequency is higher than the resonant frequency of the LC network. Therefore, the number of capacitors coupled in series between the source half-bridge circuit and the sink half-bridge circuit can be limited so that the switching frequency remains higher than the resonant frequency of the LC network.

[0090] FIG. 19 is a schematic diagram of an active cell balancing circuit including a disconnection switch coupled between the capacitors. To reduce the number of capacitors coupled in series, the disconnection switch can be opened. The half-bridge circuit and disconnection switch of FIG. 19 are similar to those shown in FIG. 14. In FIG. 19, the active cell balancing circuit includes half-bridge circuits 1400 and 1402, inductors 1902 and 1906, capacitors 1904 and 1908, and a transistor 1404. In some examples, the active cell balancing circuit may include two or more half-bridge circuits. A first terminal of inductor 1902 is coupled to the switch node of half-bridge circuit 1402, and a first terminal of inductor 1906 is coupled to the switch node of half-bridge circuit 1400. A transistor 1404 is coupled between a second terminal of inductor 1906 and capacitor 1904. Capacitor 1904 is coupled between transistor 1404 and the second terminal of inductor 1902. The capacitor 1908 is coupled to the second terminal of the inductor 1906 .

[0091] The active cell balancing circuit may include any number of instances of transistor 1404. For example, the active cell balancing circuit may include an instance of transistor 1404 in each half-bridge circuit, or an instance of transistor 1404 in every other half-bridge circuit, or every fourth half-bridge circuit, every tenth half-bridge circuit, etc. The half-bridge circuits, transistor 1404, and control circuit 308 may be included within integrated circuit 330.

[0092] The control circuit 308 includes an output coupled to the control terminal of the transistor 1404. The control circuit 308 controls the control signal C based on the AB_CTL. D to control the on / off of transistor 1404. Transistor 1404 can control the number of capacitors (e.g., capacitors 1904 and 1908) that are coupled in series.

[0093] In some examples, half bridge 1400 may be a first set of M half bridges coupled together by M−1 instances of capacitors, and half bridge 1402 may be another set of M half bridges coupled by M−1 instances of capacitors, similar to that shown in FIG. 18A. By enabling or disabling transistor 1404, the total number of capacitors in the current conduction path between a pair of charge-transferring half bridges may be limited to M−1, thereby setting an upper limit for the resonant frequency below the switching frequency. Also, when no charge is being transferred between the first set of M half bridges and the second set of M half bridges, transistor 1404 may be disabled, thereby avoiding switching of any intervening half bridges between the first set of M half bridges and the second set of M half bridges.

[0094] FIG. 20 is a block diagram of an example of an active cell balancing circuit 1706 including a network of parallel capacitors 2002. In FIG. 20, the active cell balancing circuit 1706 includes n half-bridge circuits 2004 and an inductor 2006 coupled to the switch node of each half-bridge circuit. The network of parallel capacitors 2002 includes a first set of capacitors 2008, a second set of capacitors 2010, a third set of capacitors 2012, and a fourth set of capacitors 2014. The first set of capacitors 2008 are coupled to the inductors as shown in FIG. 17. The first set of capacitors 2008 may include one capacitor for each half-bridge circuit. The second set of capacitors 2010 are coupled in parallel with the first set of capacitors 2008. The second set of capacitors 2010 may include capacitors coupled in parallel with the m capacitors of the first set of capacitors 2008. The third set of capacitors 2012 is coupled in parallel with the second set of capacitors 2010 and the first set of capacitors 2008. The third set of capacitors 2012 may include capacitors coupled in parallel with 2m capacitors of the first set of capacitors 2008. The fourth set of capacitors 2014 may include capacitors coupled in parallel with n capacitors of the first set of capacitors 2008. Other examples of the network of parallel capacitors 2002 may include parallel levels of different numbers of capacitors, and the capacitors of each level may span a different number of capacitors of the first set of capacitors 2008.

[0095] The network of parallel capacitors 2002 increases the capacitance between the two half-bridge circuits, which reduces the resonant frequency of the LC network formed by the network of parallel capacitors 2002 and inductor 2006, allowing power transfer between half-bridge circuits that may be separated by too little capacitance using only the first set of capacitors 2008.

[0096] FIG. 21 is a schematic diagram of an example active cell balancing circuit configured for two-phase operation. The active cell balancing circuit of FIG. 21 is similar to the active cell balancing circuit of FIG. 15, but uses the LC arrangement of active cell balancing circuit 1706 instead of the LC arrangement of LC circuit 306. In the active cell balancing circuit of FIG. 21, half-bridge circuits 302 and 304, inductors 1702 and 1705, and capacitors 1704 and 1708 are configured to operate as a first phase. Half-bridge circuits 1502 and 1504, inductors 2102 and 2106, and capacitors 2104 and 2108 are configured to operate as a second phase. Half-bridge circuits 302 and 1502 are coupled in parallel with battery cell 202. Half-bridge circuits 304 and 1504 are coupled in parallel with battery cell 204. The active cell balancing circuit may include any number of series-coupled half-bridge circuits in each phase. Also shown in Figure 21 is input filter circuit 506. Some examples may include input filter circuit 606 instead of input filter circuit 506.

[0097] The control circuit 308 is coupled to the half-bridge circuits 302, 304, 1502, and 1504 and provides driver signals C1, C2, C3, C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, C16, C17, C18, C19, C20, C21, C22, C23, C24, C25, C26, C27, C28, C29, C29, C30, C31, C32, C33, C34, C35, C36, C37, C38, C39, C40, C41, C42, C43, C44, C45, C46, ​​C47, C48, C49, C50, C51, C52, C53, C54, C55 TIFF2026500953000034.tif913, C2, TIFF2026500953000035.tif813,C1', TIFF2026500953000036.tif1114, C2', and The switching of half-bridge circuits 1502 and 1504 may be 180 degrees out of phase with the switching of half-bridge circuits 302 and 304. The half-bridge circuits and control circuit 308 may be incorporated into an integrated circuit 330.

[0098] Two-phase operation reduces the current stress on the transistors in the half-bridge circuit compared to a single-phase implementation, with little or no increase in circuit area. Because two-phase operation is 180 degrees out of phase, two-phase operation can reduce the AC component of the current flowing through the input filter.

[0099] 22 is a schematic diagram of another example active cell balancing circuit 2206. The active cell balancing circuit 2206 includes half-bridge circuits 302, 304, 502, and 504 coupled to battery cells 202, 204, 508, and 510, respectively. An example of the active cell balancing circuit 2206 may include any number of half-bridge circuits coupled in series. The half-bridge circuits may be included in the integrated circuit 330. The active cell balancing circuit 2206 is similar to the active cell balancing circuit 1706, except that the inductors and capacitors are swapped compared to the active cell balancing circuit 1706. In the active cell balancing circuit 2206, the inductors are coupled in series, and the capacitors are coupled between the switch nodes of the half-bridge circuits and the series inductors. Therefore, in the active cell balancing circuit 2206, the path between the two half-bridge circuits includes only an inductor and two capacitors, which reduces the capacitance reduction and resulting increase in resonant frequency caused by series-coupled capacitors. The active cell balancing circuit 2206 may also include the input filter circuit 506 or the input filter circuit 606. In FIG. 22, the active cell balancing circuit 2206 including the input filter circuit 506 is shown.

[0100] In the active cell balancing circuit 2206, a capacitor is coupled to the switch node of each half-bridge circuit. A first terminal of capacitor 2202 is coupled to the switch node of half-bridge circuit 302. A first terminal of capacitor 2205 is coupled to the switch node of half-bridge circuit 304. A first terminal of capacitor 2210 is coupled to the switch node of half-bridge circuit 502. A first terminal of capacitor 2214 is coupled to the switch node of battery cell 510. An inductor is coupled between the capacitors coupled to the switch nodes of the subsequent half-bridge circuit. Inductor 2204 is coupled between the second terminal of capacitor 2202 and the second terminal of capacitor 2205. Inductor 2208 is coupled between the second terminal of capacitor 2205 and the second terminal of capacitor 2210. Inductor 2212 is coupled between the second terminal of capacitor 2210 and the second terminal of another capacitor (e.g., capacitor 2214).

[0101] A control circuit 308 is coupled to the half-bridge circuits 302, 304, 502, and 504. The control circuit 308 generates driver signals that control switching in the half-bridge circuits. The half-bridge switching for transferring charge between two batteries may be the same as that described in FIG. 4. In the active cell balancing circuit 2206, similar to the active cell balancing circuit 206, the control circuit 308 switches all half-bridge circuits when charge is transferred between any two battery cells (see, for example, FIGS. 9A / 9B, 10A / 10B, 11A / 11B, and 12A / 12B).

[0102] FIG. 23 is a schematic diagram of an example of an active cell balancing circuit 2206 including a disconnection switch. The disconnection switch can be opened to reduce the number of inductors coupled in series. The half-bridge circuit and disconnection switch of FIG. 23 are similar to those shown in FIG. 14. In FIG. 23, the active cell balancing circuit includes half-bridge circuits 1400 and 1402, capacitors 2302 and 2306, inductors 2304 and 2308, and a transistor 1404. In some examples, the active cell balancing circuit may include two or more half-bridge circuits, capacitors, and inductors. A first terminal of capacitor 2302 is coupled to the switch node of half-bridge circuit 1402, and a first terminal of capacitor 2306 is coupled to the switch node of half-bridge circuit 1400. A transistor 1404 is coupled between a second terminal of capacitor 2306 and inductor 2304. Inductor 2304 is coupled between transistor 1404 and the second terminal of capacitor 2302. Inductor 2308 is coupled to the second terminal of capacitor 2306.

[0103] The active cell balancing circuit may include any number of instances of transistor 1404. For example, the active cell balancing circuit may include an instance of transistor 1404 in each half-bridge circuit (between each pair of adjacent half-bridge circuits), or an instance of transistor 1404 in every other half-bridge circuit, or every fourth half-bridge circuit, every tenth half-bridge circuit, etc. The half-bridge circuits, transistor 1404, and control circuit 308 may be included in integrated circuit 330.

[0104] Control circuit 308 includes an output coupled to the control terminal of transistor 1404. Control circuit 308 generates a control signal C that controls the on / off of transistor 1404 based on AB_CTL. DTransistor 1404 may, in some examples, reduce the number of series-coupled inductors (e.g., inductors 2304 and 2308) that must be controlled and the number of half-bridge circuits that are switched during charge transfer, as described in connection with FIG.

[0105] FIG. 24 is a schematic diagram of an active cell balancing circuit configured for two-phase operation based on active cell balancing circuit 2206. The active cell balancing circuit of FIG. 24 is similar to the active cell balancing circuit of FIG. 15, but uses the LC arrangement of active cell balancing circuit 2206 instead of the LC arrangement of active cell balancing circuit 206. In the active cell balancing circuit of FIG. 24, half-bridge circuits 302 and 304, capacitors 2202 and 2205, and inductors 2204 and 2208 are configured to operate as a first phase. Half-bridge circuits 1502 and 1504, capacitors 2402 and 2406, and inductors 2404 and 2408 are configured to operate as a second phase. Half-bridge circuits 302 and 1502 are coupled in parallel to battery cells 202. Half-bridge circuits 304 and 1504 are coupled in parallel to battery cells 204. The active cell balancing circuit may include any number of half-bridge circuits coupled in series in each phase. Also shown in Figure 24 is input filter circuit 506. Some examples may include input filter circuit 606 instead of input filter circuit 506.

[0106] The control circuit 308 is coupled to the half-bridge circuits 302, 304, 1502, and 1504 and provides driver signals C1, C2, C3, C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, C16, C17, C18, C19, C20, C21, C22, C23, C24, C25, C26, C27, C28, C29, C29, C30, C31, C32, C33, C34, C35, C36, C37, C38, C39, C40, C41, C42, C43, C44, C45, C46, ​​C47, C48, C49, C50, C51, C52, C53, C54, C55 TIFF2026500953000038.tif913, C2, TIFF2026500953000039.tif913,C1', TIFF2026500953000040.tif1114, C2', and Generates TIFF2026500953000041.tif1014. Control circuit 308 may generate driver signals such that the switching of half-bridge circuits 1502 and 1504 is 180 degrees out of phase with the switching of half-bridge circuits 302 and 304. The half-bridge circuits and control circuit 308 may be incorporated into an integrated circuit 330.

[0107] Two-phase operation reduces the current stress on the transistors in the half-bridge circuit with little or no increase in circuit area compared to a single-phase implementation. Because the two phases operate 180° out of phase, two-phase operation can reduce the AC component of the current flowing through the input filter.

[0108] FIG. 25 is a schematic diagram of another example active cell balancing circuit 2506. The active cell balancing circuit 2506 includes half-bridge circuits 302, 304, 502, and 504 coupled to battery cells 202, 204, 508, and 510, respectively. An example of the active cell balancing circuit 2506 may include any number of half-bridge circuits coupled in series. The half-bridge circuits may be included in the integrated circuit 330. The active cell balancing circuit 2506 is similar to the active cell balancing circuit 2206, except that in the active cell balancing circuit 2506, an inductor is coupled in series with a capacitor to the switch nodes of the half-bridge circuits. Thus, in the active cell balancing circuit 2506, the path between the two half-bridge circuits may include only two inductors and two capacitors. The active cell balancing circuit 2506 may also include an input filter circuit 506 or an input filter circuit 606. In FIG. 25, the active cell balancing circuit 2506 is shown as including an input filter circuit 506 .

[0109] A capacitor is coupled to the switch node of each half-bridge circuit. A first terminal of capacitor 2202 is coupled to the switch node of half-bridge circuit 302. A first terminal of capacitor 2205 is coupled to the switch node of half-bridge circuit 304. A first terminal of capacitor 2210 is coupled to the switch node of half-bridge circuit 502. A first terminal of capacitor 2214 is coupled to the switch node of battery cell 510.

[0110] An inductor is coupled in series with each capacitor. A first terminal of inductor 2504 is coupled to the second terminal of capacitor 2202. A first terminal of inductor 2508 is coupled to the second terminal of capacitor 2205. A first terminal of inductor 2512 is coupled to the second terminal of capacitor 2210. A first terminal of inductor 2516 is coupled to the second terminal of capacitor 2214. A second terminal of inductor 2504 is coupled to the second terminal of inductor 2508, the second terminal of inductor 2512, and the second terminal of inductor 2516.

[0111] A control circuit 308 is coupled to the half-bridge circuits 302, 304, 502, and 504. The control circuit 308 generates driver signals that control switching in the half-bridge circuits. The half-bridge switching for transferring charge between two batteries may be the same as that described in FIGS. 18A / 18B. In the active cell balancing circuit 2506, similar to the active cell balancing circuit 1706, the control circuit 308 may only switch the source half-bridge circuit and the sink half-bridge circuit when charge is transferred between any two battery cells.

[0112] FIG. 26 is a schematic diagram of an example of an active cell balancing circuit 2506 including a disconnection switch. The disconnection switch can be opened to isolate a selected set of half-bridge circuits. The half-bridge circuits and disconnection switch of FIG. 26 are similar to those shown in FIG. 14. In FIG. 26, the active cell balancing circuit includes half-bridge circuits 1400 and 1402, capacitors 2602 and 2606, inductors 2604 and 2608, and transistor 1404. In some examples, the active cell balancing circuit may include two or more half-bridge circuits. A first terminal of capacitor 2602 is coupled to the switch node of half-bridge circuit 1402, and a first terminal of capacitor 2606 is coupled to the switch node of half-bridge circuit 1400. An inductor 2604 is coupled in series with capacitor 2602, and an inductor 2608 is coupled in series with capacitor 2600. A first terminal of inductor 2608 is coupled to the second terminal of capacitor 2602, and a first terminal of inductor 2608 is coupled to the second terminal of capacitor 2606. Transistor 1404 is coupled between the second terminal of inductor 2604 and the second terminal of inductor 2608.

[0113] The active cell balancing circuit 2506 may include any number of instances of the transistor 1404. For example, the active cell balancing circuit may include an instance of the transistor 1404 for each half-bridge circuit (between a pair of adjacent half-bridge circuits), or an instance of the transistor 1404 for every other half-bridge circuit, or every fourth half-bridge circuit, every tenth half-bridge circuit, etc. The half-bridge circuits, the transistor 1404, and the control circuit 308 may be included in the integrated circuit 330.

[0114] The control circuit 308 includes an output coupled to the control terminal of the transistor 1404. The control circuit 308 generates a control signal C that controls the on / off of the transistor 1404 based on the AB_CTL. DThe transistor 1404 allows for selective control of the number of half-bridge circuits coupled via the LC circuit.

[0115] FIG. 27 is a schematic diagram of an active cell balancing circuit configured for two-phase operation based on active cell balancing circuit 2506. The active cell balancing circuit of FIG. 27 is similar to the active cell balancing circuit of FIG. 15, but uses the LC arrangement of active cell balancing circuit 2506 instead of the LC arrangement of active cell balancing circuit 206. In the active cell balancing circuit of FIG. 27, half-bridge circuits 302 and 304, capacitors 2202 and 2205, and inductors 2504 and 2508 are configured to operate as a first phase. Half-bridge circuits 1502 and 1504, capacitors 2702 and 2706, and inductors 2704 and 2708 are configured to operate as a second phase. Half-bridge circuits 302 and 1502 are coupled in parallel with battery cells 202. Half-bridge circuits 304 and 1504 are coupled in parallel with battery cells 204. The active cell balancing circuit may include any number of half-bridge circuits coupled in series in each phase. Also shown in Figure 27 is input filter circuit 506. Some examples may include input filter circuit 606 instead of input filter circuit 506.

[0116] The control circuit 308 is coupled to the half-bridge circuits 302, 304, 1502, and 1504 and provides driver signals C1, C2, C3, C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, C16, C17, C18, C19, C20, C21, C22, C23, C24, C25, C26, C27, C28, C29, C29, C30, C31, C32, C33, C34, C35, C36, C37, C38, C39, C40, C41, C42, C43, C44, C45, C46, ​​C47, C48, C49, C50, C51, C52, C53, C54, C55 TIFF2026500953000042.tif913, C2, TIFF2026500953000043.tif913,C1', TIFF2026500953000044.tif1114, C2', and Generates TIFF2026500953000045.tif1014. Control circuit 308 may generate driver signals such that the switching of half-bridge circuits 1502 and 1504 is 180° out of sync with the switching of half-bridge circuits 302 and 304. The half-bridge circuits and control circuit 308 may be incorporated into an integrated circuit 330.

[0117] Two-phase operation reduces the current stress on the transistors in the half-bridge circuit with little or no increase in circuit area compared to a single-phase implementation. Because the two phases operate 180 degrees out of phase, two-phase operation can reduce the AC component of the current flowing through the input filter.

[0118] 28 is a block diagram of a battery assembly 2800 including balancing across battery modules. The battery assembly 2800 includes battery modules 28021 and 28022. k Each battery module 28021 includes m battery cells 28041 to 28044, each coupled to an active cell balancing circuit 28061. m The active cell balancing circuit 28061 includes the battery cells 28041 to 28044 of the battery module 28021. m The battery module 28022 is coupled in series with the battery module 28021 and includes m battery cells 2804, each coupled to an active cell balancing circuit 28062. m-1 ~2804 2m The active cell balancing circuit 28062 includes a m+i ~2804 2m balances the charge between the battery module 2802 k are coupled in series to the battery module 28022 and include an active cell balancing circuit 2806 k m battery cells 2804, each coupled to n-m ~2804n Active cell balancing circuit 2806 k Battery module 2802 k Battery cell 2804 n-m ~2804 n Active cell balancing circuits 28061, 28062, and 2806 k may be an example of the active cell balancing circuit 206, the active cell balancing circuit 1706, the active cell balancing circuit 2206, the active cell balancing circuit 2506, or any other active cell balancing circuit described herein.

[0119] The battery assembly 2800 also includes a battery module balancing circuit 2807. The battery module balancing circuit 2807 balances the battery modules 28021 to 28022. k The battery module balancing circuit 2807 balances the charges between the half-bridge circuits 28081 and 28082 to 28088. k , control circuit 2814, components 28101 and 28102 to 2810 k , and components 28121 to 2812 k-1 Includes half-bridge circuits 28081 and 28082 to 2808 k The half-bridge circuits 28081 and 28082 through 28088 may be the same as the half-bridge circuit 302 with transistors rated for the battery module voltage. k The control circuit 2814 generates driver signals S1, S2, S3, S4, S5, S6, S7, S8, S9, S10, S11, S12, S13, S14, S15, S16, S17, S18, S19, S20, S21, S22, S23, S24, S25, S26, S27, S28, S29, S30, S31, S32, S33, S34, S35, S46, S47, S48, S49, S50, S51, S52, S53, S54, S55, S56, S57, S58, S59, S60, S61, S62, S63, S64, S65, S66, S67, S68, S69, S70, S71, S72, S73, S TIFF2026500953000046.tif1012, S2, TIFF2026500953000047.tif1014, SK, and Generates TIFF2026500953000048.tif914.

[0120] Components 28101 to 2810 k and components 28121 to 2812k-1 As described herein, components 28101-2810 may be capacitors, inductors, conductors, or combinations thereof (e.g., series combinations). k are conductors, and components 28121 to 2812 k-1 is an example of an LC circuit 306, such as in the active cell balancing circuit 206. In such an example, the control circuit 2814 controls the switching of the half-bridge circuit as described for the active cell balancing circuit 206.

[0121] In another example, components 28101-2810, similar to the active cell balancing circuit 1706, k are inductors, and components 28121 to 2812 k-1 is a capacitor. In such an example, the control circuit 2814 controls the switching of the half-bridge circuit as described for the active cell balancing circuit 1706.

[0122] In another example, similar to the active cell balancing circuit 2206, components 28101-2810 k is a capacitor, and components 28121 to 2812 k-1 is the inductor. In such an example, the control circuit 2814 controls the switching of the half-bridge circuit as described for the active cell balancing circuit 2206.

[0123] In another example, components 28101-2810, similar to the active cell balancing circuit 2506, k is a capacitor in series with an inductor, and components 28121 to 2812 k-1 are conductors. In such an example, the control circuit 2814 controls the switching of the half-bridge circuit as described for the active cell balancing circuit 2506.

[0124] Various examples of the battery module balancing circuit 2807 include components 28121 to 28122. k-1 and / or a multi-phase circuit element as described herein.

[0125] In this description, the term "couple" may encompass a connection, communication, or signal path that enables a functional relationship consistent with the explanation of this description. For example, if device A generates a signal that controls controlling device B to perform a certain action, (a) in a first example, device A is coupled to device B by a direct connection, or (b) in a second example, device A is coupled to device B via an intervening component C, where intervening component C does not change the functional relationship between device A and device B, causing device B to be controlled by device A via a control signal generated by device A.

[0126] Also, in this description, the phrase "based on" means "based at least in part on." Thus, if X is based on Y, X can be a function of Y and any number of other factors.

[0127] A device that is "configured" to perform a certain task or function may be configured (e.g., programmed and / or hardwired) to perform that function by a manufacturer at the time of manufacture, or may be configurable (or reconfigurable) by a user after manufacture to perform that function and / or other additional or alternative functions. Such configuration may be through firmware and / or software programming of the device, or through the configuration and / or layout of hardware components, device interconnections, or a combination thereof.

[0128] As used herein, the terms "terminal," "node," "interconnect," "pin," and "lead" are used interchangeably. Unless otherwise specified to the contrary, these terms are used generally to refer to an interconnection or termination between device elements, circuit elements, integrated circuits, devices, or other electronic or semiconductor components.

[0129] A circuit or device described as including certain components may instead be adapted to be coupled to those components to form the described circuit element or device. For example, a structure described as including one or more semiconductor elements (such as transistors), one or more passive elements (such as resistors, capacitors, and / or inductors), and / or one or more sources (such as voltage and / or current sources) may instead include only the semiconductor elements within a single physical device (e.g., a semiconductor die and / or integrated circuit (IC) package) and be adapted to be coupled to at least some of the passive elements and / or sources, thereby forming the described structure, either at the time of manufacture or at a time thereafter, e.g., by an end user and / or a third party.

[0130] Although the use of particular transistors is described herein, other transistors (or equivalent devices) may alternatively be used with little or no modification to the remaining circuit elements. For example, field-effect transistors (FETs) (such as n-channel FETs (NFETs) or p-channel FETs (PFETs)), bipolar junction transistors (BJTs—e.g., NPN or PNP transistors), insulated gate bipolar transistors (IGBTs), and / or junction field-effect transistors (JFETs) may be used in place of or in conjunction with one or more of the devices described herein. The transistors may be depletion-mode devices, drain-extension devices, enhancement-mode devices, natural transistors, or other types of device structure transistors. Additionally, the devices may be implemented in or on silicon substrates (Si), silicon carbide substrates (SiC), gallium nitride substrates (GaN), or gallium arsenide substrates (GaAs).

[0131] The claims may refer to a transistor's control input and its current terminals. In the context of a FET, the control input is the gate and the current terminals are the drain and source. In the context of a BJT, the control input is the base and the current terminals are the collector and emitter.

[0132] As used herein, a reference to a FET being "on" means that the FET's conduction channel is present and drain current can flow through the FET. A reference to a FET being "off" means that the FET's conduction channel is absent and therefore no drain current can flow through the FET. However, an "off" FET may have current flowing through the transistor's body diode.

[0133] The circuits described herein are reconfigurable to include additional or different components to provide functionality at least partially similar to that available prior to the replacement of the component. Unless otherwise noted, a component depicted as a resistor generally represents any one or more elements coupled in series or parallel to provide the amount of impedance represented by the depicted resistor. For example, a resistor described herein as a single component may instead be multiple resistors or capacitors, each coupled in parallel between the same nodes. For example, a resistor or capacitor illustrated and described herein as a single component may instead be multiple resistors or capacitors, each coupled in series between the same two nodes as a single resistor or capacitor.

[0134] While some elements of the illustrated examples are included in an integrated circuit and other elements are external to the integrated circuit, in other examples, additional or fewer features may be incorporated into the integrated circuit. Also, some or all of the features shown as being external to the integrated circuit may be included in the integrated circuit, and / or some features shown as being internal to the integrated circuit may be incorporated outside the integrated circuit. As used herein, the term "integrated circuit" means one or more circuits (1) incorporated within / on a semiconductor substrate, (2) incorporated within a single semiconductor package, (3) incorporated within the same module, and / or (4) incorporated within / on the same printed circuit board.

[0135] Modifications in the described embodiments are possible, and other embodiments are possible, within the scope of the appended claims.

Claims

1. 1. An integrated circuit (IC), comprising: a first transistor coupled between the first battery terminal and the first inductor terminal, the first transistor having a first transistor control terminal; a second transistor coupled between the first inductor terminal and a second battery terminal, the second transistor having a second transistor control terminal; a third transistor coupled between a third battery terminal and the second inductor terminal, the third transistor having a third transistor control terminal, the third battery terminal being coupled to the second battery terminal; a fourth transistor coupled between the second inductor terminal and a fourth battery terminal, the fourth transistor having a fourth transistor control terminal; a control circuit having a control input and first, second, third, and fourth control outputs, the first control output coupled to the first transistor control terminal, the second control output coupled to the second transistor control terminal, the third control output coupled to the third transistor control terminal, and the fourth control output coupled to the fourth transistor control terminal; Including, IC.

2. 2. The IC of claim 1, wherein the control circuitry responds to a control signal by: providing a first driver signal having a first state at the first control output and a second driver signal having a second state at the second control output within a first portion of a first switching cycle; providing the first driver signal having a second state at the first control output and the second driver signal having a first state at the second control output during a second portion of the first switching cycle; providing a third driver signal having a first state at the third control output and a fourth driver signal having a second state at the fourth control output within a first portion of a second switching cycle; providing the third driver signal having a second state at the third control output and the fourth driver signal having a first state at the fourth control output during a second portion of the second switching cycle; It is configured as follows: the first transistor is enabled in response to the first driver signal having the first state and is disabled in response to the first driver signal having the second state; the second transistor is enabled in response to the second driver signal having the first state and is disabled in response to the second driver signal having the second state; the third transistor is enabled in response to the third driver signal having the first state and is disabled in response to the third driver signal having the second state; the fourth transistor is disabled in response to the fourth driver signal having the second state and is enabled in response to the fourth driver signal having the first state; IC.

3. 3. The IC of claim 2, wherein the control circuit is configured to set an interval between a first transition of the first driver signal from the second state to the first state and a second transition of the third driver signal from the second state to the first state in response to the control signal indicating a transition of charge between the first battery terminal and the third battery terminal, and between the second battery terminal and the fourth battery terminal, the interval being based on an amount of current transferred.

4. 4. The IC of claim 3, wherein the control circuit is configured to provide the second transition of the third driver signal at the interval before the first transition of the first driver signal in response to the control signal indicating the transfer of the charge from the third battery terminal to the first battery terminal and from the fourth battery terminal to the second battery terminal.

5. 4. The IC of claim 3, wherein the control circuit is configured to provide the second transition of the third driver signal at the interval after the first transition of the first driver signal in response to the control signal indicating the transfer of the charge from the first battery terminal to the third battery terminal and from the second battery terminal to the fourth battery terminal.

6. 4. The IC of claim 3, wherein the spacing is based on at least one of a voltage difference between the first battery terminal and the third battery terminal, or an inductance of an inductor coupled to the first inductor terminal.

7. 10. The IC of claim 1, a first inductor coupled between the first inductor terminal and a first IC terminal; a second inductor coupled between the second inductor terminal and a second IC terminal; The IC further comprises:

8. 8. The IC of claim 7, further comprising a switch coupled between the first IC terminal and the first inductor, the control circuit having a fifth control output coupled to a switch control terminal of the switch.

9. 1. An integrated circuit (IC), comprising: a first transistor coupled between the first battery terminal and the first capacitor terminal, the first transistor having a first transistor control terminal; a second transistor coupled between the first capacitor terminal and a second battery terminal, the second transistor having a second transistor control terminal; a third transistor coupled between a third battery terminal and the second capacitor terminal, the third transistor having a third transistor control terminal, the third battery terminal being coupled to the second battery terminal; a fourth transistor coupled between the second capacitor terminal and a fourth battery terminal, the fourth transistor having a fourth transistor control terminal; a control circuit having a control input and first, second, third, and fourth control outputs, the first control output coupled to the first transistor control terminal, the second control output coupled to the second transistor control terminal, the third control output coupled to the third transistor control terminal, and the fourth control output coupled to the fourth transistor control terminal; Including, IC.

10. 10. The IC of claim 9, The control circuit responds to a control signal by providing a first driver signal having a first state at the first control output and a second driver signal having a second state at the second control output within a first portion of a first switching cycle; providing the first driver signal having a second state at the first control output and the second driver signal having a first state at the second control output during a second portion of the first switching cycle; providing a third driver signal having a first state at the third control output and a fourth driver signal having a second state at the fourth control output within a first portion of a second switching cycle; providing the third driver signal having a second state at the third control output and the fourth driver signal having a first state at the fourth control output during a second portion of the second switching cycle; It is configured as follows: the first transistor is enabled in response to the first driver signal having the first state and is disabled in response to the first driver signal having the second state; the second transistor is enabled in response to the second driver signal having the first state and is disabled in response to the second driver signal having the second state; the third transistor is enabled in response to the third driver signal having the first state and is disabled in response to the third driver signal having the second state; the fourth transistor is disabled in response to the fourth driver signal having the second state and is enabled in response to the fourth driver signal having the first state; IC.

11. 11. The IC of claim 10, wherein the control circuit is configured to set an interval between a first transition of the first driver signal from the second state to the first state and a second transition of the third driver signal from the second state to the first state in response to the control signal indicating a transfer of charge between the first battery terminal and the third battery terminal and between the second battery terminal and the fourth battery terminal, the interval being based on an amount of current transferred.

12. 12. The IC of claim 11, wherein the control circuit is configured to provide the second transition of the third driver signal at the interval before the first transition of the first driver signal in response to the control signal indicating the transfer of the charge from the third battery terminal to the first battery terminal and from the fourth battery terminal to the second battery terminal.

13. 12. The IC of claim 11, wherein the control circuit is configured to provide the second transition of the third driver signal at the interval after the first transition of the first driver signal in response to the control signal indicating the transfer of the charge from the first battery terminal to the third battery terminal and from the second battery terminal to the fourth battery terminal.

14. 13. The IC of claim 12, wherein the spacing is based on at least one of a voltage difference between the first battery terminal and the third battery terminal, or an inductance of an inductor coupled between the first capacitor terminal and the second capacitor terminal.

15. 10. The IC of claim 9, a first capacitor coupled between the first capacitor terminal and a first IC terminal; a second capacitor coupled between the second capacitor terminal and a second IC terminal; The IC further comprises:

16. 16. The IC of claim 15, further comprising a switch coupled between the first IC terminal and the first capacitor, the control circuit having a fifth control output coupled to a switch control terminal of the switch.

17. 1. An integrated circuit (IC), comprising: a first transistor coupled between the first battery terminal and the first switching terminal, the first transistor having a first transistor control terminal; a second transistor coupled between the first switching terminal and a second battery terminal, the second transistor having a second transistor control terminal; a third transistor coupled between a third battery terminal and a second switching terminal, the third transistor having a third transistor control terminal, the third battery terminal being coupled to the second battery terminal; a fourth transistor coupled between the second switching terminal and a fourth battery terminal, the fourth transistor having a fourth transistor control terminal; a first capacitor and a first inductor coupled between the first switching terminal and a first IC terminal; a second capacitor and a second inductor coupled between the second switching terminal and a second IC terminal; a control circuit having a control input and first, second, third, and fourth control outputs, the first control output coupled to the first transistor control terminal, the second control output coupled to the second transistor control terminal, the third control output coupled to the third transistor control terminal, and the fourth output coupled to the fourth transistor control terminal; Including, IC.

18. 18. The IC of claim 17, further comprising a switch coupled between the first IC terminal and the second IC terminal, the control circuit having a fifth control output coupled to a switch control terminal of the switch.

Images