A bidirectional power supply drive control board

Abstract

A bidirectional power-compensating drive control board includes a first power-compensating unit and a second power-compensating unit, characterized in that: the first power-compensating unit and the second power-compensating unit are symmetrically arranged; and the first power-compensating unit includes a bootstrap voltage input unit, a power-compensating current generation unit, and a power-compensating diode D1; wherein, the bootstrap voltage input unit collects the voltage from the bootstrap capacitor and sends it to the power-compensating current generation unit; the power-compensating current generation unit receives the voltage from the bootstrap capacitor and generates a power-compensating current; and the power-compensating diode D1 provides power to the second power-compensating unit based on the power-compensating current. Based on the solution of this invention, a bidirectional power-compensating drive control board can be provided to charge the bootstrap capacitor through mutual power-compensating between the first power-compensating unit and the second power-compensating unit.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of integrated circuits, and more particularly, to a bidirectional power supply driving control board. BACKGROUND

[0002] In a power management chip, a bootstrap capacitor circuit needs to be built for a high-side power tube to ensure the switching action of the high-side power tube. During the operation of a BUCK-BOOST converter circuit, a high-side power tube needs to be kept in a long-term on state. In order to ensure the long-term on state of the high-side power tube, it is necessary to ensure that the bootstrap capacitor of the gate voltage of the high-side power tube has sufficient charge.

[0003] In the prior art, there are usually two ways to ensure that the bootstrap capacitor has sufficient charge. The first method is to add refresh logic to the circuit, that is, when the voltage of the bootstrap capacitor is lower than a certain threshold, the high-side power tube is turned off and the low-side power tube is turned on to charge the bootstrap capacitor. The problem with this method is that every time the charge in the bootstrap capacitor is insufficient, the high-side power tube that has been in a long-term on state needs to be turned off and the low-side power tube needs to be turned on to refresh, which will cause unnecessary jitter in the output waveform, thereby affecting the quality of the output signal of the entire chip. The second method is to set up a charge pump module to continuously charge the bootstrap capacitor. The problem with this method is that an additional charge pump module needs to be added to the circuit, increasing the complexity of the circuit, and since the charge pump module has high-frequency components, it will also introduce high-frequency signals into the circuit, thereby affecting the performance of the entire chip.

[0004] Therefore, there is an urgent need for a simple and accurate power supply circuit to overcome the shortcomings of the prior art and achieve the purpose of power supply. SUMMARY

[0005] To solve the problems in the prior art, the purpose of the present application is to provide a bidirectional power supply driving control board, which charges the bootstrap capacitor through mutual charging of the first power supply unit and the second power supply unit.

[0006] The present application adopts the following technical solutions.

[0007] A bidirectional power supply driving control board, comprising a first power supply unit and a second power supply unit, characterized in that: the first power supply unit and the second power supply unit are symmetrically arranged; and the first power supply unit comprises a bootstrap voltage input unit, a power supply current generation unit and a power supply diode D1; wherein the bootstrap voltage input unit collects the voltage from the bootstrap capacitor and sends it to the power supply current generation unit; the power supply current generation unit receives the voltage from the bootstrap capacitor and generates a power supply current; and the power supply diode D1 charges the second power supply unit based on the power supply current.

[0008] Preferably, the power supply current generating unit comprises an amplifier EA1, an NMOS tube, and a mirror unit; wherein the amplifier EA1 is connected with the bootstrap voltage input unit at the negative phase input end, receives a reference voltage at the positive phase input end, and is connected with the gate of the NMOS tube MR1 at the output end; the source of the NMOS tube MR1 is grounded, and the drain is connected with the mirror unit; the mirror unit is respectively connected with the drain of the NMOS tube MR1 and the anode of the diode.

[0009] Preferably, the mirror unit comprises a first NMOS tube MP1 and a second NMOS tube MP2 connected in mirror; wherein the drain and the gate of the first NMOS tube MP1 are connected with the drain of the NMOS tube MR1 and the gate of the second NMOS tube; the drain of the second NMOS tube MP2 is connected with the anode of the diode D1; and the sources of the first NMOS tube MP1 and the second NMOS tube MP2 are connected.

[0010] Preferably, the anode of the power supply diode D1 is connected with the sources of a third NMOS tube MP3 and a fourth NMOS tube MP4 in the mirror unit in the second power supply unit.

[0011] Preferably, the source voltages of the first NMOS tube MP1 and the second NMOS tube MP2 are the first bootstrap voltage BST1, and the source voltages of the third NMOS tube MP3 and the fourth NMOS tube MP4 are the second bootstrap voltage BST2.

[0012] The application has the advantages that, compared with the prior art, the bidirectional power supply driving control board of the application has a simple structure and accurate output, and can realize bidirectional power supply of the driving control board without additional refresh logic or charge pump module, and the process of power supply does not cause large amplitude jitter of the output waveform or introduction of high frequency noise signals.

[0013] The application also has the advantages that:

[0014] 1. The application can adjust through a loop, reduce voltage ripples of the bootstrap capacitors C1 and C2, and thus reduce changes of the on-resistance of the high-side power tube.

[0015] 2. The application automatically adjusts the size of the charging current output by the power supply diode according to the voltage drop from the bootstrap capacitor, so as to realize fast power supply when the bootstrap capacitor voltage is low, slow power supply when the bootstrap capacitor voltage is high, and stable state when the bootstrap capacitor voltage reaches a preset value. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 FIG. 1 is a BUCK-BOOST converter circuit schematic diagram of a driving control board in the prior art;

[0017] Figure 2A circuit schematic diagram of a bidirectional power compensation driving control board according to the present application;

[0018] Figure 3 A schematic diagram of a generated power compensation current changing with time in a bidirectional power compensation driving control board according to the present application. DETAILED DESCRIPTION

[0019] The present application will be further described below with reference to the accompanying drawings. The following examples are only used to more clearly illustrate the technical solutions of the present application, and cannot be used to limit the protection scope of the present application.

[0020] Figure 1 A BUCK-BOOST converter circuit schematic diagram of a driving control board in the prior art according to the present application. As shown in the figure, Figure 1 the BUCK-BOOST converter includes four switch MOS tubes. Two of the switch MOS tubes MH1 and MH2 are high-side power tubes, the drains of which are connected to the input voltage terminal and the output voltage terminal respectively, the sources of which are connected to the two ends of the inductor coils SW1 and SW2, and the gates and the sources of which are respectively connected to bootstrap capacitors C1 and C2 and high-side drive levels in parallel. The other two switch MOS tubes ML1 and ML2 are low-side power tubes, the drains of which are connected to the two ends of the inductor coils SW1 and SW2 respectively, the sources of which are grounded, and the gates of which are connected to a low-side drive level. HDR1, HDR2, LDR1 and LDR2 in the circuit are gate drive signals of the four switch tubes MH1, MH2, ML1 and ML2 respectively.

[0021] Figure 2 A circuit schematic diagram of a bidirectional power compensation driving control board according to the present application. As shown in the figure, Figure 2 a bidirectional power compensation driving control board includes a first power compensation unit and a second power compensation unit. The first power compensation unit and the second power compensation unit are symmetrically arranged; and the first power compensation unit includes a bootstrap voltage input unit, a power compensation current generation unit and a power compensation diode D1. The bootstrap voltage input unit collects the voltage from the bootstrap capacitor and sends it to the power compensation current generation unit. The power compensation current generation unit receives the voltage from the bootstrap capacitor and generates a power compensation current. The power compensation diode D1 compensates the power for the second power compensation unit based on the power compensation current.

[0022] It can be understood that the first power supply unit receives the input voltage of the bootstrap capacitor and compares it with the reference voltage, and divides it into two cases: the input voltage of the bootstrap capacitor is higher than the reference voltage and the input voltage of the bootstrap capacitor is lower than the reference voltage, and then generates the current of the diode according to the determination of the above-mentioned cases, that is, the power supply current. The power supply diode D1 is connected with the second power supply unit to increase the bootstrap voltage BST2. Since the first power supply unit and the second power supply unit are symmetrically connected in the bidirectional power supply circuit, the power supply diode D2 in the second power supply unit can also supply power to the first power supply unit in the same way.

[0023] Preferably, the power supply current generating unit comprises an amplifier EA1, an NMOS tube, a mirror unit; wherein the amplifier EA1 is connected with the bootstrap voltage input unit at the negative phase input end, receives the reference voltage at the positive phase input end, and is connected with the gate of the NMOS tube MR1 at the output end; the source of the NMOS tube MR1 is grounded, and the drain is connected with the mirror unit; the mirror unit is connected with the drain of the NMOS tube MR1 and the anode of the diode respectively.

[0024] Preferably, the mirror unit comprises a first PMOS tube MP1 and a second PMOS tube MP2 connected in mirror; wherein the drain and the gate of the first PMOS tube MP1 are connected with the drain of the NMOS tube MR1 and the gate of the second PMOS tube; the drain of the second PMOS tube MP2 is connected with the anode of the diode D1; the sources of the first PMOS tube MP1 and the second PMOS tube MP2 are connected.

[0025] Preferably, the cathode of the power supply diode D1 is connected with the sources of the third PMOS tube MP3 and the fourth PMOS tube MP4 in the mirror unit in the second power supply unit.

[0026] Preferably, the source voltages of the first PMOS tube MP1 and the second PMOS tube MP2 are the first bootstrap voltage BST1, and the source voltages of the third PMOS tube MP3 and the fourth PMOS tube MP4 are the second bootstrap voltage BST2.

[0027] Specifically, the voltage input from the bootstrap capacitor C2 at the port of the first bootstrap voltage BST2 is input into the negative phase input end of the amplifier. Assuming that the high-side power tube MP3, MP4 at the port of the second bootstrap voltage BST2 is in a long-term conduction state at this time, the error amplifier EA1 can calculate the voltage drop VC2 from the bootstrap capacitor C2 and compare it with the reference voltage Vref as a reference, so as to adjust the gate voltage of the MOS tube MR1 according to the difference between the two.

[0028] Figure 3 A schematic diagram of the power supply current generated in the bidirectional power supply driving control board of the application changing with time. As shown in FIG. 6, the power supply current generated in the bidirectional power supply driving control board of the application changes with time. Figure 3As shown, during the time period t1-t2, the MOSFET containing BST1 is in the on state, and BST1 is at a high voltage. At this time, when the voltage drop VC2 from the bootstrap capacitor C2 is lower than the preset adjustment value Vreg, EA1 can control the MOSFET MR1 to generate a compensation current. This compensation current flows into the compensation diode D1 through the current mirror composed of the two MOSFETs.

[0029] It should be noted that the preset adjustment value Vreg is obtained based on the reference voltage Vref, and typically has... ,in, This is a proportionality coefficient. In one embodiment of the present invention, In practical applications, a scaling factor can be assigned. With different constant values. When the proportional coefficient is not 1, the input of the negative phase input terminal of the error amplifier EA1 can be adjusted accordingly. Then the voltage output at the output terminal of error amplifier EA1 is ,in, The gain of error amplifier EA1, This is the voltage at the non-inverting input terminal. This is the negative phase input voltage.

[0030] During the time interval t1-t2, since the voltage at port BST1 is higher than that at BST2, the charging diode charges port BST2 in the second charging unit with forward current. Because the charging diode D1 continuously charges BST2 during this time, the bootstrap capacitor C2 is in a charging state, and therefore the voltage drop VC2 from the bootstrap capacitor C2 gradually increases and remains at Vreg.

[0031] When time period t2 is reached, the MOSFET containing BST1 is turned off. At this time, the BST1 port is at a low voltage, the compensation diode D1 is turned off, and the bootstrap capacitor C2 cannot be compensated. Therefore, the voltage drop VC2 from the bootstrap capacitor C2 gradually decreases due to its own consumption. It is not until time t3 that the MOSFET containing BST1 is turned on again, which causes the voltage drop VC2 from the bootstrap capacitor C2 to gradually increase and recover to Vreg, and the compensation process is repeated.

[0032] As the MOSFET BST1 repeatedly switches between off and on states, the circuit continuously supplies power to the bootstrap capacitor C2. Similarly, when the high-side power transistors MP1 and MP2 at the port of the first bootstrap voltage BST1 are in a long-term on state, the circuit also continuously supplies power to the bootstrap capacitor C1 as MP3 and MP4 switch between on and off states. Therefore, the circuit achieves bidirectional power supply functionality.

[0033] In the above process, with the size of the voltage difference between the voltage drop VC2 from the bootstrap capacitor C2 and the preset adjustment value Vreg, the current of the power supply diode D1 also changes in steps. And according to the step current change to promote different time period power supply speed.

[0034] The beneficial effects of the present application are that compared with the prior art, the bidirectional power supply driving control board of the present application has simple structure and accurate output, and can realize bidirectional power supply of the driving control board without additional refresh logic or charge pump module. In the process of power supply, it will not cause large amplitude jitter of output waveform or introduction of high frequency noise signal.

[0035] The beneficial effects of the present application also include:

[0036] 1. The present application can reduce the output ripple caused by the pressure difference of bootstrap capacitors C1 and C3 in different voltage states through loop adjustment, thereby reducing the change of the on-resistance of the high-side power tube.

[0037] 2. The present application automatically adjusts the size of the charging current output by the power supply diode according to the voltage drop from the bootstrap capacitor, thereby realizing fast power supply when the bootstrap capacitor voltage is low, slow power supply when the bootstrap capacitor voltage is high, and stable state when the bootstrap capacitor voltage reaches the preset value.

[0038] The applicant of the present application has made a detailed description and explanation of the embodiment of the present application in combination with the drawings of the specification. However, those skilled in the art should understand that the above embodiment is only a preferred embodiment of the present application, and the detailed description is only to help the reader better understand the spirit of the present application, and is not a limitation on the protection scope of the present application. On the contrary, any improvement or modification based on the spirit of the present application should fall within the protection scope of the present application.

Claims

1. A bidirectional power supply drive control board, comprising a first power supply unit and a second power supply unit, characterized in that: The first power replenishment unit and the second power replenishment unit are symmetrically arranged; and... The first power supply unit includes a bootstrap voltage input unit, a power supply current generation unit, and a power supply diode D1; wherein, The bootstrap voltage input unit collects the voltage drop of the bootstrap capacitor and sends it to the supplementary current generation unit; The supplementary current generation unit receives the voltage drop of the bootstrap capacitor and compares the voltage drop with the reference voltage, classifying it into two cases: the voltage drop of the bootstrap capacitor is higher than the reference voltage and the voltage drop of the bootstrap capacitor is lower than the reference voltage. Based on the determination of the above cases, the current of the supplementary diode is generated, which is the supplementary current; the supplementary diode D1 supplements the second supplementary unit based on the supplementary current. The supplementary current generation unit includes an amplifier EA1, an NMOS transistor MR1, and a mirror unit; wherein... The amplifier EA1 has its negative input terminal connected to the bootstrap voltage input unit, its positive input terminal receiving a reference voltage, and its output terminal connected to the gate of the NMOS transistor MR1. The source of the NMOS transistor MR1 is grounded, and its drain is connected to the mirror unit. The mirror unit is connected to the drain of the NMOS transistor MR1 and the anode of the diode, respectively. The mirror unit includes a first PMOS transistor MP1 and a second PMOS transistor MP2 that are mirror-connected; wherein... The drain and gate of the first PMOS transistor MP1 are connected to the drain of the NMOS transistor MR1 and the gate of the second PMOS transistor. The drain of the second PMOS transistor MP2 is connected to the positive terminal of the diode D1; The source terminals of the first PMOS transistor MP1 and the second PMOS transistor MP2 are connected; The negative terminal of the supplementary diode D1 is connected to the source terminals of the third PMOS transistor MP3 and the fourth PMOS transistor MP4 in the mirror unit of the second supplementary unit. The source voltage of the first PMOS transistor MP1 and the second PMOS transistor MP2 is the first bootstrap voltage BST1, and the source voltage of the third PMOS transistor MP3 and the fourth PMOS transistor MP4 is the second bootstrap voltage BST2.

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