Power converter efficiency boost at low loads to maintain maximum constant switching frequency operating range

Abstract

The disclosure relates to power converter efficiency enhancement at low loads to maintain a maximum constant switching frequency operating range. A switched mode power supply supplies power to a load. The circuit arrangement of the power supply of the present disclosure may be configured to operate at a constant switching frequency over a range of input voltages and a range of load power requirements. The circuit arrangement of the present disclosure may modulate a minimum on-time (Tonmin) of a duty cycle of an operating frequency of a circuit based on a magnitude of an input voltage. The circuit arrangement may also operate in a continuous conduction mode (CCM) or a discontinuous conduction mode (DCM) based on the operating region. The operating region is based on a combination of a demand (Iout) from the load and an input voltage (Vin). The circuit arrangement of the present disclosure may enter the operating area based on a first combination, but exit the operating area in a second and different combination of Iout and Vin.

Description

Technical Field

[0001] The present disclosure relates to techniques for operating power converter circuits, particularly techniques for operating the circuits at low loads. Background Art

[0002] A power converter circuit can receive electrical power from a power source, convert the power in some manner, and provide the converted power to a load. In some examples, a power converter can receive alternating current (AC) power and provide direct current (DC) power to a load. In other examples, a power converter can provide AC power converted from a DC power converter (e.g., a battery) to, for example, an electric motor. Other types of power converters can also include converting DC power from one voltage level to another voltage level. A DC power converter receiving power from a battery can be configured to output a predetermined output voltage, while the input voltage can vary depending on the charge level of the battery. Summary of the invention

[0003] In general, the present disclosure describes a switch mode power supply that supplies power to a DC load and receives a DC input power. The circuit device of the power supply of the present disclosure can be configured to operate at a constant switching frequency within a range of input voltages and a range of load power requirements. The circuit device of the present disclosure can modulate the minimum on-time (Ton_min) of the duty cycle of the operating frequency of the circuit based on the amplitude of the input voltage. The circuit device can also operate in different modes based on the operating region, such as a continuous conduction mode (CCM) or a discontinuous conduction mode (DCM). The operating region is based on a combination of a demand from a load (e.g., an output current (Iout)) and an input voltage (Vin). The circuit device of the present disclosure can enter an operating region based on a first combination, but exit the operating region at a second and different combination of Iout and Vin. The control circuit device for the present disclosure can be implemented in a variety of ways, some of which include analog circuit devices, digital circuit devices including analog-to-digital converters (ADCs) in some examples, logic circuit devices, or some combination of circuit types.

[0004] In one example, the present disclosure describes a circuit comprising an input terminal configured to receive an input voltage; and a modulation circuit device connected to the input terminal, wherein the modulation circuit device is configured to define a minimum on-time based on the input voltage, wherein the minimum on-time is proportional to the inverse of the amplitude of the input voltage, and wherein the minimum on-time is a minimum duration of the on-time of the duty cycle of the operating frequency of the circuit.

[0005] In another example, the present disclosure describes a system comprising an output terminal configured to deliver power to a load; an input terminal configured to receive an input voltage; and a modulation circuit device connected to the input terminal and the output terminal and configured to define a minimum on-time based on the input voltage, wherein the regulation is proportional to the inverse of the amplitude of the input voltage, and wherein the minimum on-time is a minimum duration of the on-time of the duty cycle of the operating frequency of the circuit.

[0006] In another example, the present disclosure describes a method comprising receiving an input voltage at an input terminal; and receiving the input voltage by a modulation circuit device connected to the input terminal; generating, by the modulation circuit device, an adjustment of a minimum on-time based on the input voltage, wherein the adjustment is proportional to an inverse of the amplitude of the input voltage, and wherein the minimum on-time is a minimum duration of an on-time of a duty cycle of an operating frequency of the circuit.

[0007] The details of one or more examples of the present disclosure are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the present disclosure will be apparent from the description and drawings, and from the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 is a block diagram illustrating an example power converter system of the present disclosure;

[0009] Figure 2A and Figure 2B is a diagram illustrating an example operation of a circuit device of the present disclosure implementing Ton_min modulation;

[0010] Figure 3 is a diagram illustrating an example operation of the circuit device of the present disclosure to vary the entry and exit thresholds of the DPFM;

[0011] Figure 4 is a graph illustrating a user-selectable tradeoff of low load performance efficiency and constant frequency operating range for a circuit arrangement of the present disclosure;

[0012] Figure 5A is a diagram showing an example of modulating the minimum on-time of a power converter circuit of the present disclosure;

[0013] Figure 5B is a circuit diagram of an example analog circuit implementation of the Ton_min modulation circuit of the present disclosure;

[0014] Figure 6 is a schematic diagram illustrating an example implementation of a circuit arrangement of the present disclosure, the circuit arrangement being configured to clip Ton_min at a higher input voltage;

[0015] Figure 7is an example schematic diagram showing an example analog implementation of a circuit device of the present disclosure, the circuit device being configured to adjust Ton_min, adjust T DPFM and offsetting the DPFM exit threshold boundary;

[0016] Figure 8 is a timing diagram showing an example of an extended period of time in DPFM; and

[0017] Fig. 9 is a flow chart illustrating an example operation of a circuit device of the present disclosure. DETAILED DESCRIPTION

[0018] The present disclosure describes a power supply implemented in a circuit device, which is configured to modulate the minimum on-time (Ton_min) of the duty cycle of the circuit based on the amplitude of the input voltage. The power supply is also configured to operate in different modes, such as a continuous conduction mode (CCM) or a discontinuous conduction mode (DCM), and to adjust the combination of conditions that trigger the power supply to exit a given operating mode to be different from the combination of conditions that trigger the power supply to enter the operating mode. In this way, compared to other types of power supply circuits, the power supply of the present disclosure can operate at a constant frequency under a wide range of conditions (input voltage and load demand), while also operating at a higher efficiency under light loads.

[0019] Figure 1 is a block diagram illustrating an example power converter system of the present disclosure. Figure 1 The system 100 in the example of FIG. 1 includes a switch mode power supply that provides power to a DC load 140 and receives DC input power from a battery. The system 100 may include a decoupling circuit device 101, which may include a filtering circuit, for example, using resistors, capacitors, inductors, and semiconductors ( Figure 1 ), the filtering circuit can help prevent noise and other unwanted interference from reaching the input terminal Vin 104 and affecting the operation of the power converter 120.

[0020] In some examples, system 100 may also include output circuitry that may include inductors, capacitors, and other circuitry to condition and filter power from switch node Vsw 106 of power converter 120 before providing power to DC load 140 via output terminal Vout 132. In some examples, output circuitry 130 may include a voltage sampling circuit, such as a resistor divider ( Figure 1 ), to sense the output voltage at Vout 132. Figure 1In the example of FIG. 1 , the sense output voltage of power converter 120 may be externally adjustable, and Vout-sense 134 may come from a resistor divider or similar circuit of output circuitry 130 . In other examples, the output sense circuit may be internal to power converter 120 .

[0021] exist Figure 1 In an example, the circuitry of power converter 120 includes a driver and switch 118, such as a half-bridge, full-bridge, or similar switching circuit under the control of control logic 114. Protection circuitry 116 can monitor power converter 120 and protect power converter 120 from fault conditions such as overvoltage, overcurrent, excessive temperature, or other fault conditions. In other examples, power converter 120 can include an analog control loop instead of logic circuitry 114.

[0022] In some examples, power converter 120 can be configured as a buck converter to reduce the input voltage amplitude at Vin 104 to a reduced amplitude voltage at Vout 132. In other examples, power converter 120 can be configured as a boost converter, a buck-boost converter, or some other type of switch-mode power supply. In the example of a buck converter, output circuitry 130 can include, for example, an output inductor circuit having an inductance L. Other examples of power supplies can include a boost converter, a buck-boost converter, or other types of converters.

[0023] The system 100 also includes a Ton_min circuit device 110 that can adjust the minimum on-time as the input voltage at Vin 104 changes. As described above, as the battery is charged and discharged, the voltage Vbatt 102 output from the battery can change based on the state of charge of the battery (also known as the depth of discharge (DOD)). Vin 104 can also change based on the larger system ( Figure 1 For example, Vin 104 may change due to any of several operating transients (e.g., "cold start", pin short circuit interruption, etc.) that are also described in the LV 124 automotive test standard, which includes quality and reliability tests such as how to subject the system to electrical disturbances that simulate electrical disturbances in the automotive electrical system during driving.

[0024] The Ton_min circuit device 110 can also be connected to T DPFM Circuit device 112. When operating in deep PFM (DPFM), T DPFM The circuit device 112 can adjust Ton_min and adjust T DPFMTo make DPFM exit the threshold boundary deviation. In other words, T DPFM The circuit device 112 can be configured to increase the threshold cycle duration so that the circuit enters DPFM with a first set of operating conditions of input voltage and output current, and the circuit exits DPFM with a second set of operating conditions. In some examples, the circuit of the present disclosure can operate in DPFM for light loads, for example when the load requires only a small amount of current, such as in a "sleep" mode or other similar low current mode. For example, when the switching period becomes greater than an internally defined time reference T at a lower load, the switching period may be increased to a threshold cycle duration. DPFM When , the circuit device of the present disclosure can enter DPFM.

[0025] Vin 104 includes an input terminal for a power converter 120, and Vin 104 can be configured to receive an input voltage from Vbatt 102, which can be regulated and filtered by a decoupling circuit device 101. The Ton_min circuit device 110 can include a modulation circuit device connected to the input terminal Vin 104. The Ton_min circuit device 110 can be configured to define a minimum on-time based on the input voltage. Specifically, for the switch mode power supply of the present disclosure, the Ton_min circuit device 110 modulates the minimum on-time to be proportional to the inverse of the amplitude of the input voltage. For some low values ​​of Vin 104 (e.g., low Vbatt 102), and for some high values ​​of Vin, the Ton_min circuit device 110 can be configured to limit the minimum on-time, for example, setting the minimum on-time to a constant that does not depend on the amplitude of Vin 104.

[0026] In the context of switching power supplies, particularly buck power converters, the phrase minimum on-time can refer to the minimum duration of the on-time of the duty cycle of the operating frequency of the circuit. For a buck converter, the maximum switching frequency depends on the "minimum on-time" of the converter. The minimum on-time can depend on the speed limitations of the internal circuitry and the limitations of the configuration for control loop stability. For Figure 1 In the digital example shown, the timing and logic circuitry within controller 114 that switches from one state to another can only switch as fast as the choice of components allows. Wider bandwidth circuitry can operate with narrower pulse widths.

[0027] Therefore, the "minimum on time" has a specific meaning based on the implementation of the power converter circuit. The exact value of the "minimum on time" may depend on the technology and voltage category, for example, a power converter with a voltage greater than 50V may be operated using different circuit devices and different timings than a power converter with a voltage such as 12V or lower. For example, for the driver and switch 118, a specific circuit device selection may define the speed of the switching cycle (e.g., closing and turning off). Therefore, the "minimum on time" Ton_min may also be defined based on the amount of charge that can be transferred during the switching cycle. In this way, Ton_min may be a selected design criterion based on the application and implementation of the power converter circuit. For some circuits such as system 100 that include both digital circuit devices and analog circuit devices, if the analog circuit device operation cycle is slower than the speed of the digital circuit device, the analog circuit device may be a limiting factor in determining Ton_min. Similarly, if the digital circuit device speed (e.g., based on clock, loop stability or other factors) is slower than the analog circuit device, the digital circuit device limitation may determine Ton_min.

[0028] In some examples, the minimum on-time may be related to the peak output current limit. A current-controlled power converter with a current sensing circuit may have taken some time to sense the output current Iout 136. This sensing time may be on the order of about 60ns. For such a circuit, Ton_min may be set to 60ns or longer to allow the current sensing circuit to determine Iout 136. In other examples, a voltage-controlled power converter may have a Ton_min as low as 10ns because the voltage sensing circuit may operate faster than the current sensing circuit.

[0029] The circuit device of the present disclosure can modulate the minimum on-time Ton_min based on the input voltage Vin 104, but keep the same duty cycle in some operation modes. The power converter 120 can operate in at least one of pulse width modulation (PWM) continuous conduction mode (CCM), PWM discontinuous conduction mode (DCM), pulse frequency modulation (PFM) CCM or PFM-DCM, and DPFM.

[0030] Continuous or discontinuous conduction refers to whether the current in the energy storage element (e.g., an inductor in the example of a buck converter) goes to zero in each switching cycle. In the example of system 100, the energy storage element (e.g., an inductor) Figure 11) may be located in the output circuit device 130. In CCM, the current does not reach zero, so some energy is left at the end of each switching cycle. The power converter 120 may add energy to the energy storage element in the next cycle so that the current does not go to zero. In DCM, all of the energy of each cycle is used up, and the inductor has no current and no stored energy during a portion of each switching cycle.

[0031] The energy stored by the system 100 (e.g., in reactive circuit components, such as the inductance L of the output circuit device 130) can be related to the output power provided to the load. Operating in DCM or CCM depends on the input voltage Vin 104 and the output load demand. When Vin 104 is low and the load demand is high (e.g., higher output current Iout 136), the power converter 120 can operate in CCM, and can switch to DCM for high Vin 104 and / or reduced load demand (e.g., lower Iout 136). In an example of the present disclosure, the control logic 114 can operate the power converter 120 using pulse width modulation (PWM) for higher current loads and pulse frequency modulation (PFM) for high Vin 104 and / or lower current load Iout 136.

[0032] The Ton_min circuit device 110 may also limit the minimum on-time at lower input voltages and higher input voltages, rather than strictly adhering to the regulation of Ton_min based on 1 / Vin. In other words, in response to the magnitude of the input voltage being less than or equal to the first threshold voltage, the Ton_min circuit device 110 may set the minimum on-time to a first fixed value. Similarly, in response to the magnitude of the input voltage exceeding the second threshold voltage, the Ton_min circuit device 110 may set the minimum on-time to a second fixed value. As described above, the Ton_min circuit device 110 may be implemented as an analog circuit device, a digital circuit device, or some combination of circuit devices. In other examples, the Ton_min circuit device 110 may operate within a range of Ton_min, for example, a Ton_min range with a high threshold and a low threshold, rather than limiting Ton_min based on Vin 104.

[0033] The system 100 of the present disclosure may provide advantages over other types of power converter systems. By modulating Ton_min as Vin 104 changes, the circuit device of the present disclosure may maintain a constant operating frequency over a wide range of conditions (e.g., the range of variation of Vin 104 and the range of variation of Iout 136). The constant operating frequency at medium to high load demands (e.g., greater than 100 mA in some examples) may indicate that the power converter of the present disclosure operates with electromagnetic compatibility (EMC) performance that may reduce or eliminate other parts of the system ( Figure 1 136 ) can be implemented to reduce electromagnetic interference (EMI) of the output current (not shown). For example, in an electric vehicle or similar system that includes components that are sensitive to EMI (e.g., processors, sensing circuits, and the like), reduced EMI can mean more reliable system operation, reduced shielding requirements, and reduced costs. Note that the Iout 136 threshold indicating "medium to high load demand" can be flexibly implemented to a range of output current magnitudes by the power converter circuit device of the present disclosure, and in some examples can be less than 100 mA or greater than 100 mA.

[0034] In this disclosure, "constant frequency" operation or "fixed frequency" refers to an operating frequency that varies within a relatively small range of a desired frequency. Some small variations in operating frequency (e.g., within a few Hertz of the desired frequency) may still be considered "constant frequency". The frequency range variation around the operating frequency may be on the order of + / -5% or + / -10%, and may be defined by the tolerances of the electrical components used in the circuit arrangement.

[0035] In addition, for example, for Vin 104, modulating Ton_min and limiting Ton_min under predetermined conditions can result in higher circuit operating efficiency, especially at lower load demands, such as in the range of 10mA or less. In some examples, the efficiency of the power converter of the present disclosure can be improved by more than 40% over similar types of power converters. As with the above-mentioned medium to high load demand threshold, the "lower load demand" threshold can be selected as a design criterion and can be flexibly implemented by the circuit device of the present disclosure, and can be less than 10mA or greater than 10mA in other examples.

[0036] In some applications, improved efficiency at low loads means that fewer emissions, such as CO, are generated when the product is operated in a low power mode. 2 During the product's life, the 2The overall impact of the savings can be high because some applications of the power converters of the present disclosure can be operated in a low power mode for a significant percentage of the time compared to a higher power mode. For example, some systems for electric or hybrid vehicles can be operated in a sleep mode or other low power mode for a net longer duration than when driving over the life of the vehicle.

[0037] Figure 2A and Figure 2B is a diagram showing an example performance of a circuit device of the present disclosure implementing two Ton_min modulations. Figure 1 As described above, the power converter of the present disclosure can also operate in different modes based on the operating region. The operating region is based on a combination of the demand from the load (e.g., output current (Iout)) and the input voltage (Vin). Figure 2A and Figure 2B The example values ​​listed on the X-axis and Y-axis of FIG. 1 are merely example values ​​used to describe the power converter of the present disclosure. In other examples, the values ​​of the output current, input voltage, and the location of the operating region boundary may be different from Figure 2A and Figure 2B Examples in .

[0038] exist Figure 2A In the example of FIG. 1 , the circuit arrangement of the power converter can operate in the PWM CCM 202 region for lower input voltages and for combinations of higher input voltages and higher output currents (e.g., higher load demands). The CCM to DCM boundary is shown by 210. In this way, the power converter can continue to use constant frequency PWM for combinations of lower Iout over a range of input voltages in the PWM DCM 204 region.

[0039] In contrast to the circuit arrangement of the present disclosure, for an example of a power converter circuit operating with a fixed Ton_min, e.g. Figure 2B As shown in Ton_min 260, the boundary between operating in PWM DCM 204 and changing to pulse frequency modulation in the PFM DCM 206 region is indicated by 216. By implementing step 1 of the present disclosure, for example, modulating Ton_min based on 1 / Vin, the power converter of the circuit arrangement can shift the boundary (218) from 216 to 212. In this way, the power converter of the present disclosure can operate at reduced load demands (at Figure 2A By limiting the Ton_min modulation 258, for example, for Vin above the threshold 254, for higher load currents (e.g., for Figure 2AFor example, constant frequency operation for load currents greater than about 100 mA is constant. Figure 1 As mentioned, operating at a constant frequency may result in better EMC performance when compared to a varying operating frequency.

[0040] Similarly, in the example of a power converter circuit operating at a fixed Ton_min 260, the boundary between operating at PFM DCM 206 and changing to deep pulse frequency modulation in the DPFM 208 region is indicated by 222, for example, for light load requirements, such as low Iout of less than about 40 mA. By implementing step 1 of the present disclosure, the power converter of the circuit arrangement can shift the boundary (220) from 222 to 226. This shift can improve the efficiency of low Iout (e.g., hibernation or sleep mode) when compared to operating at a fixed Ton_min. Figure 2A In the example of FIG. 1 , for a combination of higher Vin and higher Iout, the boundary 224 between the DPFM 208 operation and the PFM DCM 206 may be given by:

[0041]

[0042] Where T DPFM is the threshold duration of the operating PFM period, and L is the inductance of the energy storage device, as described above with respect to Figure 1 described.

[0043] In some examples, step 1 of the present disclosure also includes a step for low Vin (eg, Figure 1 In other words, in response to the amplitude of the input voltage being less than or equal to the threshold voltage 252, the Ton_min modulation circuit device of the present disclosure can set the minimum on-time to a fixed value 256. Figure 2B In the example of , for values ​​of Vin less than about 8 volts, the Ton_min modulation circuit device can fix Ton_min to about 225 milliseconds (ns). As described above, these values ​​are just examples to help explain the operation of the circuit device of the present disclosure. In other examples, for input voltages less than threshold 252, the Ton_min modulation circuit device can use a different Vin lower limit threshold 252 and can set Ton_min to a different duration 256.

[0044] The Ton_min modulation circuit device of the present disclosure (for example, Figure 1The Ton_min circuit arrangement 110 of FIG. 110 may also perform the second step in response to the power converter operating in DPFM 208. When operating in PFM-DCM 206, and the load demand decreases such that the power converter operates across boundary 226 and enters DPFM 208, and in response to the associated operating cycle exceeding the threshold cycle duration T DPFM , the Ton_min modulation circuit device can increase the minimum on-time Ton_min. The circuit device can also increase the threshold T DPFM As a result, the circuit may enter DPFM 208 operation based on boundary 226, but the increase in Ton_min and T DPFM The increase in Iout causes a shift in boundary 226, causing circuit operation to exit DPFM 208 to enter PFM-DCM 206 based on a combination of conditions of Iout and Vin that is different than the combination of conditions under which circuit operation enters DPFM 208. This increase in the minimum on time can further increase conversion efficiency in this region of operation.

[0045] Figure 3 is a diagram illustrating an example operation of the circuit device of the present disclosure to change the entry and exit thresholds of the DPFM. Figure 2A and Figure 2B As described above, the Ton_min modulation circuit arrangement of the present disclosure may be configured to offset the boundary between the DPFM 308 and the PFM-DMC 306 .

[0046] In some examples, for a power converter circuit, such as the buck converter described in the present disclosure, in order to maximize the operating conditions of the power converter operating in PWM-CCM 302, Ton_min should be relatively small. In addition, a power converter operating at a constant frequency can provide better EMC performance than operating in PFM. In other words, in order to reduce the operating region of PFM, the duration of Ton_min should be relatively short. However, when the load (e.g., Figure 1 There is also a tradeoff in operating at a desired efficiency when the load 140 has low demand (e.g., in sleep mode). Figure 3 Examples and Figure 2A As shown, as the load current demand decreases, the power converter circuit of the present disclosure can cross over from PWM-CCM 302 to PWM-DCM 304, and to PFM-DCM 306. For low Iout and Vin greater than 6 volts, Figure 3 In the example of FIG. 3 , the power converter may enter DPFM 308, for example, when operating condition boundary 326 is crossed. The condition for entering DPFM 308 may also be described as a PFM period greater than a threshold period T DPFM The conditions, as mentioned above, Figure 2A , Figure 2B and Figure 7 described.

[0047] When the Ton_min modulation circuit device determines that the power converter is operating in DPFM 308, the Ton_min modulation circuit device of the present disclosure may increase Ton_min and increase T DPFM .like Figure 3 As mentioned above, the increase of Ton_min and T DPFM The increase in Ton_min causes the power converter DPFM entry threshold 326 to shift so that the exit threshold boundary becomes 328. In other words, the increase in Ton_min after entering DPFM can provide increased efficiency. As a side effect, the increase in Ton_min can also shift the DPFM exit threshold 326 on the Y-axis (to a higher Iout value 328). DPFM The increase in may compensate for this undesirable effect, thereby producing a downward shift in the DPFM exit threshold to maximize the parameter range for constant frequency operation, as shown by boundary portion 324 .

[0048] In addition, the operating mode boundaries, boundary offsets, and other features of the power converter of the present disclosure can be selected by the user to trade off efficiency with other desired performance characteristics. The details of steps 1 and 2 of the present disclosure can be flexibly configured, for example in circuit design or in silicon, to minimize drive and switching losses and optimize other performance characteristics. For the power converter of the present disclosure, the Vout ripple is the limitation, not the architecture of the circuit device. As described above with respect to Figure 1 As mentioned above, the Ton_min modulation circuit device of the present disclosure can be implemented as an analog circuit device, a digital circuit device, or some combination thereof. Figure 5B In the analog circuit device example, the circuit 500 can be configured to increase Ton_min by one or more of the following: increasing C Ton circuit capacitance of circuit 522, increase reference voltage Vref 554 or reduce the voltage injected into C Ton The amount of current 516 in circuit 522. These actions can be increased by C Ton The amount of time it takes for the circuit 522 to charge and thereby increase the time it takes for the inverting input of the comparator 540 to ramp to Vref 554 and thereby increase the time it takes for the comparator 540 to switch. This operation is also Figure 8 Shown in.

[0049] Figure 4is a chart showing a user-selectable tradeoff of low-load performance efficiency and constant frequency operating range for a circuit device of the present disclosure. As with other charts of the present disclosure, the values ​​along the X-axis and Y-axis are examples of values ​​used to describe the circuit device of the present disclosure. In other examples, the specific shape of the curve and the axis values ​​may be different.

[0050] Figure 4 The examples show the performance of different examples of the power converter circuit device of the present disclosure. Step 1 (Ton modulation) and step 2 (Ton increase in DPFM) can be flexibly and independently selected by the user of the power converter circuit device of the present disclosure. Adjusting the Ton_min modulation can balance the efficiency improvement when operating at light load with the operating range of the constant frequency range at medium and high output currents of the load. Adjusting the Ton_min increase when entering DPFM can balance the efficiency improvement at light load with Vout ripple.

[0051] Figure 5A is a graph showing an example of adjusting the minimum on-time of the power converter circuit of the present disclosure. Figure 5A An example is Figure 2B An example of a graph of , describing the modulation of Ton_min by a Ton_min modulation circuit arrangement.

[0052] Figure 5B is an example analog circuit implementation of the Ton_min modulation circuit of the present disclosure. Figure 5B The circuit 500 in the example of FIG. 1 shows an implementation of step 1 (eg, Ton_min modulation based on 1 / Vin). For step 2, the implementation of increasing Ton_min includes increasing the capacitor C Ton 522, and updating T when operating in DPFM DPFM Other steps to increase Ton_min may include decreasing current 516 or increasing the value of Vref 554, as described above. Circuit 500 is a circuit similar to that described above with respect to Figure 1 An example of the Ton modulation circuit device 110 is described.

[0053] In the example of circuit 500, the non-inverting input of operational transconductance amplifier OTA 538 receives an indication of input voltage Vin 510 via a resistor divider including resistor R1 530 in series with R2 532 and connected to Vin 510. Vin 510 is the voltage in the circuit 500 described above. Figure 1 An example of Vin 104 is described.

[0054] OTA 538 can be part of a feedback loop where the current through transistor M2 526 is based on Vin' / R3 (which is also the mirror current of current mirror 536). The first branch of mirror current 536 is connected to ground in series through the drain-source channels of M2 526 and R3 528. Feedback voltage Vfb 542 is connected to the inverting input of OTA 538 and between M2 526 and R3 528 to connect the voltage across R3 528 to OTA 538.

[0055] Current sources 512A and 512B are configured to generate the same amount of current, and the arrangement of current sources 512B and 512A will control the clipping 502 at low values ​​of the input voltage Vin 510. Current source 512A is connected between the source of N-channel MOSFET M2 526 and ground, while current source 512B is connected between the drain of M2 526 and ground. Current source 512A injects current at the source of M2 526, and current source 512B sinks current from the drain of M2 526.

[0056] Current mirror 536 is configured to output current 516, which is injected into C Ton 522. The current 516 may also be referred to as the Ton_min current i Ton-min 516. When operating in DPFM mode, switch M3 525 may receive signal DPFM 542 which may switch C Ton-DPFM 544 and C Ton 522 are added, thereby increasing the time for the inverting input of comparator 540 to charge to Vref 554. Switch M1 524 acts as a reset to discharge the capacitance of circuit 500, for example, to C Ton 522 or C Ton-DPFM 544 and C Ton 522 combined discharge.

[0057] Comparator 540 receives the voltage across C at its inverting input. Ton 522. The non-inverting input of the comparator 540 is connected to the reference voltage Vref 54. The output Ton-min 520 of the comparator 540 regulates the minimum on-time.

[0058] exist Figure 5B In the example shown, Vx / K 544 is also an input to OTA 538. Selecting the value of Vx / K 544 can control the limit 506 at the higher input voltage Vin 510, as described above with respect to Figure 1-Figure 3In this manner, by selecting components and component values ​​of circuit 500, and tuning the ratio of current mirror 536, a user can select desired performance of the Ton modulation circuit arrangement and power converter circuit.

[0059] Figure 6 6 is a schematic diagram showing an example implementation of a circuit device of the present disclosure, which is configured to limit Ton_min at a higher input voltage. Figure 5B An example of OTA 538 is described. Figure 6 In the example of FIG. 6 , circuit 600 is shown as a multi-stage OTA. Figure 6 Only the first stage of the OTA is described in detail. The OTA stage 1 output 628 is connected to the second stage 636 and any subsequent stages ( Figure 6 600 only shows one possible example implementation of a portion of the Ton_min modulation circuit device of the present disclosure. In other examples, different circuit arrangements and components may also be used.

[0060] exist Figure 6 In the above, Vin 610, Vx / K 644 and Vfb 642 are respectively Figure 5B 600 . Vsup 620 supplies power to the OTA of circuit 600 via P-channel MOSFET P1 602 . The gate of P1 602 is connected to Vgate_mirror 622 .

[0061] exist Figure 6 In the example of FIG. 5 , N-channel transistors N1 611 and N2 612 are arranged as a current mirror, with the source of N1 611 and the source of N2 612 connected to a reference voltage, such as circuit ground, and the gate of N1 611 connected to the drain of N1 611 and the drain of P-channel transistor P2 604. The drain of N2 612 is connected to the OTA stage 1 output 628 and the drain of P4 608. The gate of P2 604 is connected to Vfb 642, and the gate of P4 608 is connected to Vin 610.

[0062] The source of P1 602 is connected to Vsup 620, and the drain of P1 602 is connected to the sources of P2 604, P3 606, and P4 608. The gate of P3 606 receives Vx / K 644.

[0063] Figure 7 is an example schematic diagram showing an example analog implementation of a circuit device of the present disclosure, the circuit device being configured to adjust Ton_min, adjust T DPFM And make DPFM exit threshold boundary deviation. Figure 3 The operation of circuit 700 is described, for example, for generating T DPFM Time reference to determine the threshold for DPFM operating mode.

[0064] Circuit 700 is the same as above with respect to Figure 1 Description of T DPFM An example of a circuit device 112 and may be connected to the above Figure 5A and Figure 5B The circuit 500 is described. Figure 7 In the example, the circuit 700 includes a comparator 740, a current I tdpfm 716, output DPFM 720, reset transistor M1 724, and also includes capacitors Cdpfm_1 708 and Cdpfm_2 710 connected in parallel, and switch M3 706. Closing switch M3 706 increases the capacitance of Cdpfm, for example, Cdpfm becomes the sum of Cdpfm_1 708 and Cdpfm_2 710, and thus increases the threshold duration Tdpfm. Circuit 700 is separate from circuit 500, and Figure 5B The DPFM 542 signal corresponds to the output of the comparator 740 DPFM 720 .

[0065] The circuit 700 is arranged with the DPFM 720 as the output of the comparator 740. A reference voltage Vref 714 is connected to the inverting input and a charge voltage Vc_dpfm 712 of the capacitor circuit is connected to the non-inverting input of the comparator 740. Vref 714 may be set to be equal to the value described above with respect to Figure 5B The output of comparator 740 controls the operation of switch M3 706, which connects Cdpfm_1 708 and Cdpfm_2 710 at the node of Vc_dpfm 712. Reset switch M1 724 is configured to short the node of Vc_dpfm 712 to ground when closed. Current I tdpfm 716 is injected into one or both of capacitors Cdpfm_1 708 and Cdpfm_2 710 .

[0066] Similar to Figure 5B To increase the minimum on-time, the circuit 700 is configured to increase the minimum on-time by closing the switch M3 706, shifting (eg, increasing) Vref 714 upward, and / or reducing the current I injected into the circuit capacitance including one or both of the capacitors Cdpfm_1 708 and Cdpfm_2 710. tdpfm716 to increase the circuit capacitance. Similarly, a modulation circuit arrangement including circuit 700 is configured to increase the threshold period duration by increasing the circuit capacitance of circuit 700, increasing Vref 714 and / or reducing the current injected into the circuit capacitance.

[0067] Figure 8 814. When the load demand decreases at 820, the voltage Vc_dpfm 808 on the circuit capacitor eventually has enough time to reach the reference voltage Vref 806 at 822, which exceeds the threshold Tdpfm_1 814. When operating in DPFM, at time 822 Figure 7 Comparator 740 of DPFM 720 asserts DPFM 812, which causes Ton_min 804 to increase during the next cycle and the threshold increases to Tdpfm_2 816. When load demand 802 increases again at 824, the regulation loop reduces the switching period to a value less than Tdpfm_2 to exit the DPFM operating region (as seen in the third to last Ton_min pulse). After reset 810, the threshold moves back to Tdpfm_1 814.

[0068] Fig. 9 is a flow chart showing an example operation of the circuit device of the present disclosure. Unless otherwise specified, the Figure 1 , Figure 5A , Figure 5B and Figure 6 To describe Fig. 9 box.

[0069] Power converter systems (e.g. Figure 1 System 100 of the present invention may receive an input voltage Vin 104 (90) at an input terminal of a DC-DC power converter circuit (e.g., power converter 120). In some examples, the input voltage may vary, and power converter 120 may be configured to output a current Iout 136 to a load 140 at a consistent output voltage Vout 132 as load demand varies, even if Vin 104 varies.

[0070] A modulation circuit device (eg, Ton_min circuit device 110) of power converter 120 connected to the input terminal may also receive Vin 104 (92). Ton_min circuit device 110 may generate an adjustment to the minimum on-time (94) based on the input voltage, such as Figure 5A As shown above. Figure 1-Figure 8As described above, the Ton_min circuit device 110 can modulate Ton_min, where the regulation is proportional to the inverse of the amplitude of the input voltage, such as 1 / (Vin104), and depends on whether the operating region is DPFM. As described above, when the circuit is in an operating mode (e.g., PWM-CCM, PWM-DCM, and PFM) as described above with respect to Figure 2A , Figure 2B and Figure 3 The minimum on-time is the minimum duration of the on-time of the duty cycle of the operating frequency of the circuit when shifting between the other modes.

[0071] As mentioned above about Figure 2A , Figure 2B and Figure 3 As described above, in response to the magnitude of Vin 104 being less than or equal to the first threshold voltage 252, the Ton_min circuit device 110 may set the minimum on-time to a fixed value 256 (96). Similarly, in response to the magnitude of Vin 104 exceeding the second threshold voltage, the modulation circuit device may set the minimum on-time to a second fixed value 258 (98).

[0072] In other examples, the Ton_min circuit device can be configured to have a minimum Ton_min value 258 and a maximum Ton_min value 256, and the modulation circuit device can adjust Ton_min according to 1 / Vin without considering the threshold input voltage. In other words, as long as Ton_min is within the range between the threshold minimum Ton_min value 258 and the threshold maximum Ton_min value 256, the Ton_min circuit device 110 can maintain Ton_min according to 1 / Vin. As described above, maintaining the Ton_min value within a specified range can be described as "clipping" Ton_min.

[0073] The techniques of the present disclosure may also be described in the following example clauses.

[0074] Item 1: A circuit comprising: an input terminal configured to receive an input voltage; and a modulation circuit device connected to the input terminal, wherein the modulation circuit device is configured to define a minimum on-time based on the input voltage, wherein the minimum on-time is proportional to the inverse of the amplitude of the input voltage, and wherein the minimum on-time is a minimum duration of the on-time of the duty cycle of the operating frequency of the circuit.

[0075] Item 2. A circuit according to Item 1, wherein the modulation circuit device is further configured to: set the minimum on-time to a first fixed value in response to the amplitude of the input voltage being less than or equal to a first threshold voltage; and set the minimum on-time to a second fixed value in response to the amplitude of the input voltage exceeding a second threshold voltage.

[0076] Clause 3. A circuit as described in any of clauses 1 and 2, wherein the circuit includes a power converter circuit, the power converter circuit is configured to receive an input voltage and generate an output voltage, and wherein the circuit is configured to operate in at least one of pulse width modulation (PWM) continuous conduction mode (CCM), PWM discontinuous conduction mode (DCM), pulse frequency modulation (PFM) CCM or PFM-DCM.

[0077] Clause 4. The circuit of clause 3, wherein the operating frequency has an associated operating cycle, and wherein the minimum on-time is increased when operating in PFM and in response to the associated operating cycle exceeding a threshold cycle duration.

[0078] Clause 5. The circuit of clause 4, wherein to increase the minimum on-time, the circuit is configured to: increase circuit capacitance, shift the reference voltage upward, or reduce current injected into the circuit capacitance.

[0079] Clause 6. A circuit according to any one of clauses 4 and 5, wherein in response to an associated operating cycle exceeding a threshold cycle duration, the circuit is configured to operate in deep PFM (DPFM), and the threshold cycle duration is increased such that: the circuit enters DPFM with a first set of operating conditions of input voltage and output current, and the circuit exits DPFM with a second set of operating conditions.

[0080] Clause 7. A circuit according to any one of clauses 4 to 6, wherein the modulation circuit device includes a DPFM circuit device, which is configured to increase the threshold period duration by: increasing the circuit capacitance of the modulation circuit device, shifting the reference voltage upward, or reducing the current injected into the circuit capacitance.

[0081] Item 8. A system comprising: an output terminal configured to deliver power to a load; an input terminal configured to receive an input voltage; and a modulation circuit device connected to the input terminal and the output terminal and configured to: define a minimum on-time based on the input voltage, wherein the regulation is proportional to the inverse of the amplitude of the input voltage, and wherein the minimum on-time is a minimum duration of the on-time of the duty cycle of the operating frequency of the circuit.

[0082] Item 9. A system according to Item 8, wherein the modulation circuit device is further configured to: set the minimum on-time to a first fixed value in response to the amplitude of the input voltage being less than or equal to a first threshold voltage; and set the minimum on-time to a second fixed value in response to the amplitude of the input voltage exceeding a second threshold voltage.

[0083] Clause 10. A system as described in any of clauses 8 and 9, wherein the circuit includes a power converter circuit configured to receive an input voltage and generate an output voltage, and wherein the circuit is configured to operate in at least one of a pulse width modulation (PWM) continuous conduction mode (CCM), a PWM discontinuous conduction mode (DCM), or a pulse frequency modulation (PFM) CCM or PFM-DCM.

[0084] Clause 11. The system of clause 10, wherein the operating frequency has an associated operating cycle, and wherein the minimum on-time is increased when operating in PFM and in response to the associated operating cycle exceeding a threshold cycle duration.

[0085] Clause 12. The system of clause 11, wherein to increase the minimum on-time, the circuit is configured to: increase circuit capacitance, shift the reference voltage upward, or reduce current injected into the circuit capacitance.

[0086] Clause 13. The system of any of Clauses 11 and 12, wherein in response to the associated operating cycle exceeding a threshold cycle duration, the circuit is configured to operate in deep PFM (DPFM) and increase the threshold cycle duration.

[0087] Clause 14. The system of any of clauses 11 to 13, wherein the DPFM circuit device is configured to increase the threshold period duration by increasing a capacitance of the DPFM circuit device, increasing a reference voltage, or reducing a current injected into the capacitance of the DPFM circuit device.

[0088] Clause 15. The system of any of clauses 8 to 14, wherein the input terminal is configured to receive an input voltage from a battery.

[0089] Item 16. A method comprising: receiving an input voltage at an input terminal; and receiving the input voltage by a modulation circuit device connected to the input terminal; generating, by the modulation circuit device, an adjustment to a minimum on-time based on the input voltage, wherein the adjustment is proportional to the inverse of the amplitude of the input voltage, and wherein the minimum on-time is a minimum duration of the on-time of a duty cycle of an operating frequency of the circuit.

[0090] Item 17. The method according to Item 16 further includes: in response to the amplitude of the input voltage being less than or equal to the first threshold voltage, the modulation circuit device sets the minimum on-time to a first fixed value; and in response to the amplitude of the input voltage exceeding the second threshold voltage, the modulation circuit device sets the minimum on-time to a second fixed value.

[0091] Clause 18. A method according to any one of clauses 16 and 17, wherein the circuit includes a power converter circuit configured to receive an input voltage and generate an output voltage, the method further comprising operating in at least one of a pulse width modulation (PWM) continuous conduction mode (CCM), a PWM discontinuous conduction mode (DCM), a pulse frequency modulation (PFM) CCM, or a PFM-DCM.

[0092] Clause 19. The method of any one of clauses 16 to 18, wherein the operating frequency has an associated operating cycle, the method further comprising: operating in deep PFM (DPFM) and increasing the minimum on time in response to the associated operating cycle exceeding a threshold cycle duration.

[0093] Clause 20. The method of Clause 19, further comprising: in response to the associated operating cycle exceeding the threshold cycle duration, increasing the threshold cycle duration.

[0094] In one or more examples, the above functions can be implemented in hardware, software, firmware, or any combination thereof. Figure 1 The various components of the EMBODIMENTS 2000 may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, these functions may be stored on a tangible computer-readable storage medium and executed by a processor or a hardware-based processing unit.

[0095] Instructions may be executed by one or more processors, such as one or more digital signal processors (DSPs), general-purpose microprocessors, application-specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), or other equivalent integrated or discrete logic circuit devices. Therefore, the terms "processor" and "processing circuit device" as used herein may refer to any of the aforementioned structures or any other structure suitable for implementing the techniques described herein. In addition, these techniques may be implemented entirely in one or more circuits or logic elements.

[0096] The techniques of the present disclosure may be implemented in a variety of devices or apparatuses, including wireless handsets, integrated circuits (ICs), or a set of ICs (e.g., chipsets). Various components, modules, or units are described in this disclosure to emphasize functional aspects of devices configured to perform the disclosed techniques, but do not necessarily require implementation by different hardware units. Instead, as described above, the various units may be combined in a hardware unit or provided by a collection of interoperable hardware units, including one or more processors as described above.

[0097] Various examples of the disclosure have been described. These and other examples are within the scope of the following claims.

Claims

1. A circuit comprising: an input terminal configured to receive an input voltage; as well as a modulation circuit arrangement connected to the input terminal, wherein the modulation circuit arrangement is configured to define a minimum on-time based on the input voltage, wherein the minimum on-time is proportional to an inverse of the magnitude of the input voltage, and wherein the minimum on-time is a minimum duration of the on-time of a duty cycle of an operating frequency of the circuit.

2. The circuit according to claim 1, wherein the modulation circuit device is further configured to: In response to the magnitude of the input voltage being less than or equal to a first threshold voltage, setting the minimum on-time to a first fixed value; and In response to the magnitude of the input voltage exceeding a second threshold voltage, the minimum on-time is set to a second fixed value.

3. The circuit according to claim 1, wherein the circuit comprises a power converter circuit configured to receive the input voltage and generate an output voltage, and The circuit is configured to operate in at least one of pulse width modulation (PWM) continuous conduction mode (CCM), PWM discontinuous conduction mode (DCM), pulse frequency modulation (PFM-CCM), or PFM-DCM.

4. The circuit of claim 3, wherein the operating frequency has an associated operating cycle, the minimum on-time being increased when operating in PFM and in response to the associated operating cycle exceeding a threshold cycle duration.

5. The circuit of claim 4 , wherein in order to increase the minimum on-time, the circuit is configured as: Increase the circuit capacitance, Shift the reference voltage upward, or The current injected into the circuit capacitance is reduced.

6. The circuit of claim 4 , wherein in response to the associated operating cycle exceeding the threshold cycle duration, the circuit is configured to operate in deep PFM and increase the threshold cycle duration such that: The circuit enters deep PFM at a first set of operating conditions of the input voltage and output current, and The circuit exits deep PFM at a second set of operating conditions.

7. The circuit of claim 4 , wherein the modulation circuit arrangement is configured to increase the threshold period duration by: increasing the circuit capacitance of the modulation circuit device, Shift the reference voltage upward, or The current injected into the circuit capacitance is reduced.

8. A system comprising: output terminals configured to deliver power to a load; an input terminal configured to receive an input voltage; as well as A modulation circuit device is connected to the input terminal and the output terminal and is configured to: The minimum on-time is defined based on the input voltage, wherein the regulation is proportional to the inverse of the magnitude of the input voltage, and The minimum on-time is a minimum duration of the on-time of the duty cycle of the operating frequency of the circuit.

9. The system of claim 8, wherein the modulation circuit device is further configured to: In response to the magnitude of the input voltage being less than or equal to a first threshold voltage, setting the minimum on-time to a first fixed value; and In response to the magnitude of the input voltage exceeding a second threshold voltage, the minimum on-time is set to a second fixed value.

10. The system according to claim 8, wherein the circuit comprises a power converter circuit configured to receive the input voltage and generate the output voltage, and The circuit is configured to operate in at least one of pulse width modulation (PWM) continuous conduction mode (CCM), PWM discontinuous conduction mode (DCM), pulse frequency modulation (PFM-CCM), or PFM-DCM.

11. The system of claim 10, wherein the operating frequency has an associated operating cycle, the minimum on-time being increased when operating in PFM and in response to the associated operating cycle exceeding a threshold cycle duration.

12. The system of claim 11, wherein to increase the minimum on-time, the circuit is configured to: Increase the circuit capacitance, Shift the reference voltage upward, or The current injected into the circuit capacitance is reduced.

13. The system of claim 11, wherein in response to the associated operating cycle exceeding the threshold cycle duration, the circuit is configured to operate in deep PFM and increase the threshold cycle duration.

14. The system of claim 11, wherein the deep PFM circuitry is configured to increase both the minimum on-time and the threshold period duration by increasing a capacitance of the deep PFM circuitry.

15. The system of claim 8, wherein the input terminal is configured to receive the input voltage from a battery.

16. A method comprising: receiving an input voltage at an input terminal of the power converter; as well as receiving the input voltage by a modulation circuit arrangement of the power converter connected to the input terminal; generating, by the modulation circuit means, an adjustment for a minimum on-time based on the input voltage, wherein the regulation is proportional to the inverse of the magnitude of the input voltage, and The minimum on-time is a minimum duration of the on-time of the duty cycle of the operating frequency of the circuit.

17. The method according to claim 16, further comprising: In response to the amplitude of the input voltage being less than or equal to a first threshold voltage, the modulation circuit device sets the minimum on-time to a first fixed value; as well as In response to the magnitude of the input voltage exceeding a second threshold voltage, the minimum on-time is set by the modulation circuit device to a second fixed value.

18. The method of claim 16, wherein the circuit comprises a power converter circuit configured to receive the input voltage and generate an output voltage, the method further comprising operating the circuit in at least one of pulse width modulation (PWM) continuous conduction mode (CCM), PWM discontinuous conduction mode (DCM), pulse frequency modulation (PFM-CCM), or PFM-DCM.

19. The method of claim 16, wherein the operating frequency has an associated operating cycle, the method further comprising: In response to the associated operating cycle exceeding a threshold cycle duration, operating in deep PFM and increasing the minimum on-time.

20. The method according to claim 19, further comprising: In response to the associated operating cycle exceeding the threshold cycle duration, the threshold cycle duration is increased.

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