Output pre-charging control circuit of battery boost converter

Abstract

The utility model discloses a battery boost converter output pre-charging control circuit, which belongs to the technical field of electric energy conversion and comprises a battery, a battery boost converter, a hardware sampling circuit, a microcontroller, a pre-charging circuit, a first capacitor, a second capacitor and a load. The hardware sampling circuit comprises a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor and a detection circuit, a first output end and a second output end of the battery boost converter are respectively connected with the hardware sampling circuit, and the fifth resistor is connected with the third resistor in series through a first switch. The output pre-charging control circuit of the battery boost converter is small in size and high in reliability, the pre-charging circuit is simple, extra pre-charging signals are not needed, whether a load is connected or removed is judged through an existing sampling circuit, the setting of an output terminal and an output signal is simplified, and the circuit is convenient to use. The output pre-charging control circuit of the battery boost converter can improve the endurance of the battery.

Description

Technical Field

[0001] This application relates to the field of power conversion technology, and in particular to a precharge control circuit for the output of a battery boost converter. Background Technology

[0002] When the battery boost converter and the battery are integrated together, the battery serves as the input to the boost converter. As long as the input is not turned off, there will always be an output voltage. To solve this problem, a precharge control signal is added to the output terminal of the converter. However, the above method requires increasing the size of the output terminal of the converter, and the addition of the precharge signal also reduces the reliability. Summary of the Invention

[0003] This application aims to provide a simple and reliable battery boost converter output precharge control circuit.

[0004] To achieve the above objectives, the technical solution of this application is: a pre-charge control circuit for the output of a battery boost converter, comprising:

[0005] A battery boost converter, wherein the input terminal of the battery boost converter is connected to a battery;

[0006] The first capacitor has its first end connected to the first output terminal of the battery boost converter, and its second end connected to the second output terminal of the battery boost converter.

[0007] The hardware sampling circuit includes a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, and a detection circuit. The first and second output terminals of the battery boost converter are respectively connected to the hardware sampling circuit. The fifth resistor is connected in series with the third resistor through a first switch.

[0008] The pre-charge circuit includes a sixth resistor and a second switch, wherein the sixth resistor and the second switch are connected in series, and the pre-charge circuit is connected in parallel with the first switch;

[0009] The microcontroller is connected to the detection circuit, the first switch, and the second switch, and is connected to the battery boost converter via a drive converter.

[0010] The second capacitor is connected to both the hardware sampling circuit and the pre-charge circuit.

[0011] The load is connected in parallel with the second capacitor.

[0012] Optionally, the detection circuit includes:

[0013] A microcurrent sampling and detection circuit is provided, wherein the input terminal of the microcurrent sampling and detection circuit is connected between the fifth resistor and the first switch, and is also connected to one end of the pre-charge circuit; the output terminal of the microcurrent sampling and detection circuit is connected to the microcontroller.

[0014] A current sampling and detection circuit is provided, wherein the input terminal of the current sampling and detection circuit is connected between the fifth resistor and the first switch, and is also connected to one end of the pre-charge circuit; the output terminal of the current sampling and detection circuit is connected to the microcontroller.

[0015] A positive voltage detection circuit is provided, wherein the input terminal of the positive voltage detection circuit is connected between the first resistor and the second resistor; and the output terminal of the positive voltage detection circuit is connected to the microcontroller.

[0016] The output negative voltage detection circuit has its input terminal connected between the third resistor and the fourth resistor; its output terminal is connected to the microcontroller.

[0017] Optionally, the first resistor is grounded through the second resistor; the third resistor is grounded through the fourth resistor; and the first terminal of the first capacitor is grounded.

[0018] Optionally, the microcontroller includes a CPU module, an AD module, a GPIO module, and a PWM module; the AD module is connected between the CPU module and the micro-current sampling and detection circuit, the current sampling and detection circuit, the output positive voltage detection circuit, and the output negative voltage detection circuit; the PWM module is connected between the CPU module and the drive converter; and the GPIO module is connected between the CPU module and the first switch and the second switch.

[0019] Optionally, the micro-current sampling and detection circuit, the current sampling and detection circuit, the output positive voltage detection circuit, and the output negative voltage detection circuit each include: a first operational amplifier, a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, and a third capacitor; the seventh resistor is connected between the input terminal of the detection circuit and the negative input terminal of the first operational amplifier; the positive input terminal of the first operational amplifier is grounded through the eighth resistor; the ninth resistor is connected between the output terminal of the detection circuit and the output terminal of the first operational amplifier; the output terminal of the first operational amplifier is grounded through the ninth resistor and the third capacitor; and the tenth resistor is connected between the negative input terminal of the first operational amplifier and the output terminal of the first operational amplifier.

[0020] Optionally, the microcurrent sampling and detection circuit further includes: a first diode and a second diode; the output terminal of the first operational amplifier is grounded through the first diode and the second diode.

[0021] Optionally, the microcontroller includes a digital signal processor or a microcontroller unit.

[0022] Optionally, the battery boost converter includes a BOOST converter or an isolated boost converter.

[0023] The beneficial effects of this application are as follows: the precharge circuit is simple and does not require an additional precharge signal. It uses the existing sampling circuit to determine whether the load is connected or removed, which simplifies the output terminal and output signal settings. It can determine that the load is disconnected and enter the power saving mode to save battery power and improve battery life. The entire battery boost converter output precharge control circuit is small in size and has high reliability.

[0024] To make the above-mentioned features and advantages of the application more apparent and understandable, specific embodiments are provided below, and detailed descriptions are given in conjunction with the accompanying drawings. Attached Figure Description

[0025] Figure 1 This is a circuit diagram of a first specific embodiment of a battery boost converter output precharge control circuit according to this application.

[0026] Figure 2 for Figure 1 The circuit diagram of the output positive voltage detection circuit.

[0027] Figure 3 for Figure 1 The circuit diagram of the output negative voltage detection circuit.

[0028] Figure 4 for Figure 1 The circuit diagram of the current sampling and detection circuit in the image.

[0029] Figure 5 for Figure 1 The circuit diagram of the microcurrent sampling and detection circuit in the image.

[0030] Figure 6 This is a circuit diagram of a second specific embodiment of a battery boost converter output precharge control circuit according to this application.

[0031] Figure 7 This is a circuit diagram of a third specific embodiment of a battery boost converter output precharge control circuit according to this application.

[0032] In the accompanying drawings, similar reference numerals refer to the same elements. Detailed Implementation

[0033] To make the objectives and technical solutions of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the described embodiments of this application without creative effort are within the scope of protection of this application.

[0034] In one embodiment of this application, please refer to Figure 1 This application provides a pre-charge control circuit for the output of a battery boost converter, comprising:

[0035] Battery boost converter 10, the input terminal of which is connected to a battery;

[0036] Capacitor C1, with its first end connected to the first output terminal of the battery boost converter and its second end connected to the second output terminal of the battery boost converter;

[0037] The hardware sampling circuit includes resistors R2, R3, R4, R5, and R6, and a detection circuit. The first and second output terminals of the battery boost converter 10 are respectively connected to the hardware sampling circuit. Resistor R6 is connected in series with resistor R4 through switch Q1.

[0038] The pre-charge circuit 12 includes a resistor R1 and a switch Q2, wherein the resistor R1 and the switch Q2 are connected in series, and the pre-charge circuit 12 is connected in parallel with the switch Q1.

[0039] The microcontroller 18 is connected to the detection circuit, switch Q1 and switch Q2, and the microcontroller 18 is connected to the battery boost converter 10 through the drive converter 13.

[0040] Capacitor C2 is connected to both the hardware sampling circuit and the pre-charge circuit 12;

[0041] Load 11 is connected in parallel with capacitor C2.

[0042] As an example, the detection circuit includes:

[0043] A micro current sampling and detection circuit 14 is provided. The output terminal of the micro current sampling and detection circuit 14 is connected to the microcontroller 18, and the input terminal is connected between the resistor R6 and the switch Q1, and is also connected to one end of the pre-charge circuit 12.

[0044] The current sampling and detection circuit 15 has its output terminal connected to the microcontroller 18, its input terminal connected between the resistor R6 and the switch Q1, and connected to one end of the pre-charge circuit 12.

[0045] The positive voltage detection circuit 17 is provided, and its output terminal is connected to the microcontroller 18, while its input terminal is connected between the detection resistor R2 and the detection resistor R3.

[0046] Output negative voltage detection circuit 16, the output terminal of the output negative voltage detection circuit 16 is connected to the microcontroller 18, and the input terminal is connected between the detection resistor R4 and the detection resistor R5;

[0047] As an example, switch Q1 is the main output switch used to bypass the pre-charge circuit. The hardware sampling circuit acquires the output positive voltage Vo_P and output negative voltage Vo_N voltage signals, and sends the sampled detection signals to the microcontroller through the output positive voltage detection circuit 17 and the output negative voltage detection circuit 16; at the same time, resistor R6 acquires the output current signal, and sends it to the microcontroller through the micro current sampling detection circuit 14 and the current sampling detection circuit 15. When the microcontroller 18 detects that the output current is below 10mA through a small current sampling detection signal, it determines that the load 11 has been removed. At this time, the output voltage is lower than the input voltage, and the driving voltage of the switching transistor of the battery boost converter 10 is insufficient to drive the switching transistor. Switch Q1 is disconnected. After disconnection, the output negative voltage Vo_N signal is detected again. If it is less than R1*10mA, after a period of time, it is confirmed that the load 11 has been removed. The pre-charge switch Q2 is turned off, and the driving signal of the switching transistor of the battery boost converter 10 is disconnected to reduce the switching loss of the circuit and enter a low-power saving mode to save battery power. If it is not less than R1*10mA, switch Q1 is re-engaged to maintain the output.

[0048] Furthermore, after load 11 is removed, switches Q1 and Q2 are both open. Since resistors R2 and R3, which detect the positive output voltage Vo_P, are connected in series and grounded, and resistors R4 and R5, which detect the negative output voltage Vo_N, are connected in series and grounded, the negative output voltage Vo_N is equal to the voltage of GND, and the positive output voltage Vo_P is the battery voltage. When a jump in the negative output voltage Vo_N is detected, it indicates that an external load is connected. Then, the output voltage of the battery boost converter 10 will charge capacitor C2 sequentially through the positive output voltage Vo_P, capacitor C2, resistor R4, resistor R5 to ground. At this time, the negative output voltage Vo_N will be detected by the negative output voltage detection circuit 16 as an increase. The microcontroller 18 determines the load connection by detecting the magnitude of the rise in the output negative voltage Vo_N, then closes the precharge switch Q2 and turns on the switching transistor of the battery boost converter 10, connecting to the precharge circuit 12, so that the output voltage of the battery boost converter 10 precharges the capacitor C2 through the smaller precharge resistor R1.

[0049] Furthermore, when the microcontroller 18 detects that the output current is below 10mA through the microcurrent sampling detection signal, it determines that the pre-charging is over, closes the switch Q1, bypasses the pre-charging circuit 12, and disconnects the drive signal of the switching transistor of the battery boost converter 10 to prevent arcing through the contact terminal when the capacitor C2 is connected, thus ensuring the safety of the pre-charging control circuit of the battery boost converter output.

[0050] As an example, the microcontroller 18 includes a CPU module, an AD module, a GPIO module, and a PWM module; the AD module is connected between the CPU module and the micro current sampling and detection circuit 14, the current sampling and detection circuit 15, the output positive voltage detection circuit 17, and the output negative voltage detection circuit 16; the PWM module is connected between the CPU module and the drive converter 13; and the GPIO module is connected between the CPU module and the switch Q1 and the switch Q2.

[0051] As an example, the AD module acquires the output positive voltage Vo_P signal, output negative voltage Vo_N signal, output current signal, and output micro current signal of the battery boost converter 10 and inputs them to the CPU module. The CPU module calculates the output voltage setpoint based on the input voltage signal and calculates the duty cycle of the battery boost converter 10 based on the actual output voltage to determine the state of the load 11. Based on the corresponding state, the GPIO module outputs GPIO signals P1 and P2 to the drive circuits of switches Q1 and Q2 to control the conduction and cutoff of switches Q1 and Q2. At the same time, the PWM module outputs a high-frequency PWM signal to drive the converter 13. The drive converter 13 is the drive chip for the switching transistor of the battery boost converter 10 and controls the conduction and cutoff of the switching transistor of the battery boost converter 10.

[0052] The following is combined Figures 2-5 The internal structure of the detection circuit is described below. For example... Figure 2 As shown, the output positive voltage detection circuit 17 includes: operational amplifier A, resistors R21, R22, R23, R24, and capacitor C21; resistor R21 is connected between the input terminal of the output positive voltage detection circuit 17 and the negative input terminal of operational amplifier A; the positive input terminal of operational amplifier A is grounded through resistor R22; resistor R23 is connected between the output terminal of the output positive voltage detection circuit 17 and the output terminal of operational amplifier A; the output terminal of operational amplifier A is grounded through resistor R23 and capacitor C21; resistor R24 ​​is connected between the negative input terminal of operational amplifier A and the output terminal of operational amplifier A.

[0053] As an example, Figures 3-5The internal structure shown is similar to Figure 2 Similarly, I will not go into details here.

[0054] As an example, such as Figure 5 As shown, the micro-current sampling and detection circuit 14 further includes diodes D51 and D52; the output terminal of the operational amplifier A is grounded through diodes D51 and D52.

[0055] As an example, the precharge control of the battery boost converter 10 is performed during a high-speed interruption of 50kHz-100kHz.

[0056] The pre-charge circuit of this application is simple and does not require an additional pre-charge signal. It uses the existing sampling circuit to determine whether the load is connected or removed, simplifies the output terminal and output signal settings, can determine that the load is disconnected, enter the power saving mode, save battery power, improve battery life, and the overall circuit size is small and the reliability is high.

[0057] In the second embodiment of this application, please refer to Figure 6 The battery boost converter includes a BOOST converter 20; the BOOST converter 20 includes an inductor L1, a switch Q3, and a switch Q4. In this embodiment, the BOOST converter 20 is used to boost and filter the battery input current. Capacitor C1 is connected in parallel with the series branch of switches Q3 and Q4. Inductor L1 is connected to the battery through the midpoint of the series branch of switches Q3 and Q4. The PWM module of the microcontroller 18 outputs a PWM signal to the driver chips of switches Q3 and Q4 in the BOOST converter 20, i.e., the driver controller 13, to control the on / off state of switches Q3 and Q4. Specifically, the working principle of the hardware sampling circuit, the pre-charge circuit 12, and the microcontroller 18 in this embodiment is the same as in the first embodiment, and will not be repeated here.

[0058] In the third embodiment of this application, please refer to Figure 7The battery boost converter includes an isolated boost converter 30. The isolated boost converter 30 may include switches Q5, Q6, Q7, and Q8, a resonant network 301, a transformer M, and a rectifier circuit 302. In this embodiment, the isolated boost converter 30 is used to boost and filter the battery input current. The series branches of switches Q5 and Q6 and Q7 and Q8 are connected in parallel with the battery. The resonant network 301 is connected in parallel with the series branches of switches Q5 and Q6 and Q7 and Q8, and also in parallel with the primary winding of the transformer M. The secondary winding of the transformer M is connected in parallel with the rectifier circuit 302. The driver converter 13 controls the switching of the isolated boost converter 30. The filtered current output from the resonant network 301 is input to the transformer M. The rectifier circuit 302 rectifies the output current of the transformer M, thus achieving the boost filtering function. Specifically, the working principle of the hardware sampling circuit, pre-charge circuit 12 and microcontroller 18 in this embodiment is the same as that in the first embodiment, and will not be repeated here.

[0059] Although this application has been disclosed above with reference to embodiments, it is not intended to limit this application. Anyone skilled in the art may make some modifications and refinements without departing from the spirit and scope of this application. Therefore, the scope of protection of this application shall be determined by the appended claims.

Claims

1. A pre-charge control circuit for the output of a battery boost converter, characterized in that, include: A battery boost converter, wherein the input terminal of the battery boost converter is connected to a battery; The first capacitor has its first end connected to the first output terminal of the battery boost converter, and its second end connected to the second output terminal of the battery boost converter. The hardware sampling circuit includes a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, and a detection circuit. The first and second output terminals of the battery boost converter are respectively connected to the hardware sampling circuit. The fifth resistor is connected in series with the third resistor through a first switch. The pre-charge circuit includes a sixth resistor and a second switch, wherein the sixth resistor and the second switch are connected in series, and the pre-charge circuit is connected in parallel with the first switch; The microcontroller is connected to the detection circuit, the first switch, and the second switch, and is connected to the battery boost converter via a drive converter. The second capacitor is connected to both the hardware sampling circuit and the pre-charge circuit; The load is connected in parallel with the second capacitor.

2. The battery boost converter output precharge control circuit as described in claim 1, characterized in that, The detection circuit includes: A microcurrent sampling and detection circuit is provided, wherein the input terminal of the microcurrent sampling and detection circuit is connected between the fifth resistor and the first switch, and is also connected to one end of the pre-charge circuit; the output terminal of the microcurrent sampling and detection circuit is connected to the microcontroller. A current sampling and detection circuit is provided, wherein the input terminal of the current sampling and detection circuit is connected between the fifth resistor and the first switch, and is also connected to one end of the pre-charge circuit; the output terminal of the current sampling and detection circuit is connected to the microcontroller. A positive voltage detection circuit is provided, wherein the input terminal of the positive voltage detection circuit is connected between the first resistor and the second resistor; and the output terminal of the positive voltage detection circuit is connected to the microcontroller. The output negative voltage detection circuit has its input terminal connected between the third resistor and the fourth resistor; its output terminal is connected to the microcontroller.

3. The battery boost converter output precharge control circuit as described in claim 2, characterized in that, The first resistor is grounded through the second resistor; the third resistor is grounded through the fourth resistor; and the first terminal of the first capacitor is grounded.

4. The battery boost converter output precharge control circuit as described in claim 3, characterized in that, The microcontroller includes a CPU module, an AD module, a GPIO module, and a PWM module; the AD module is connected between the CPU module and the micro current sampling and detection circuit, the current sampling and detection circuit, the output positive voltage detection circuit, and the output negative voltage detection circuit; the PWM module is connected between the CPU module and the drive converter; and the GPIO module is connected between the CPU module and the first switch and the second switch.

5. The battery boost converter output precharge control circuit as described in claim 4, characterized in that, The micro-current sampling and detection circuit, the current sampling and detection circuit, the output positive voltage detection circuit, and the output negative voltage detection circuit each include: a first operational amplifier, a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, and a third capacitor; the seventh resistor is connected between the input terminal of the detection circuit and the negative input terminal of the first operational amplifier; the positive input terminal of the first operational amplifier is grounded through the eighth resistor; the ninth resistor is connected between the output terminal of the detection circuit and the output terminal of the first operational amplifier; the output terminal of the first operational amplifier is grounded through the ninth resistor and the third capacitor; the tenth resistor is connected between the negative input terminal of the first operational amplifier and the output terminal of the first operational amplifier.

6. The battery boost converter output precharge control circuit as described in claim 5, characterized in that, The microcurrent sampling and detection circuit further includes a first diode and a second diode; the output terminal of the first operational amplifier is grounded through the first diode and the second diode.

7. The battery boost converter output precharge control circuit as described in claim 1, characterized in that, The microcontroller includes a digital signal processor or a microcontroller unit.

8. The battery boost converter output precharge control circuit as described in claim 1, characterized in that, The battery boost converter includes a BOOST converter or an isolated boost converter.

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