CN114744874A - Step-down power supply circuit structure and step-down power supply - Google Patents
Step-down power supply circuit structure and step-down power supply Download PDFInfo
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- CN114744874A CN114744874A CN202210439082.4A CN202210439082A CN114744874A CN 114744874 A CN114744874 A CN 114744874A CN 202210439082 A CN202210439082 A CN 202210439082A CN 114744874 A CN114744874 A CN 114744874A
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
- H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
- H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
- H02M3/158—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators including plural semiconductor devices as final control devices for a single load
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
- H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
- H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
- H02M3/157—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators with digital control
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
- Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
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- Power Engineering (AREA)
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Abstract
The invention is suitable for the technical field of electronic circuits, and provides a voltage-reducing power supply circuit structure and electrical equipment. The embodiment of the application detects the voltage signal of the circuit input end through the main control circuit, when the voltage signal of the circuit input end is lower than the preset target voltage signal, it is determined that the voltage signal of the circuit input end and the target voltage signal meet a first condition, at the moment, the main control circuit outputs the enable control signal to the boost output circuit, the boost output circuit boosts the voltage of the circuit input end and then outputs the boosted voltage to the bootstrap capacitor for charging, the bootstrap capacitor can be bootstrapped for charging, so that the upper bridge arm switch tube reaches the on state with 100% duty ratio, the output voltage of the step-down power supply circuit structure is improved to be close to or the same as the input voltage, and the voltage drop between the input voltage and the output voltage is reduced as much as possible.
Description
Technical Field
The invention belongs to the technical field of electronic circuits, and particularly relates to a voltage reduction power supply circuit structure and a voltage reduction power supply.
Background
With the development of the diversification of the functionality of electronic products, the internal circuit of the electronic product usually includes circuit structures of different systems, and these circuit structures may work under different voltage environments, which requires the use of a voltage boosting or voltage reducing technology, such as a voltage reducing power supply, which can convert the input high voltage into a stable low voltage and then output the stable low voltage, so as to supply power to the circuit key system.
In a common MCU-controlled BUCK synchronous power supply in the market, two NMOS are generally used as switching tubes, as shown in fig. 1, wherein a driving voltage of an upper bridge arm switching tube Q1 is provided by a bootstrap capacitor C1, and when an input voltage is higher than an output voltage, and a lower bridge arm switching tube Q2 is turned on as a synchronous rectifier, a voltage output by a BUCK power supply unit charges a bootstrap capacitor C1 through a resistor R1 and a diode D1, so that a stable voltage is provided between a VB cathode and a VS pin of a chip U1 to drive the upper bridge arm switching tube Q1.
However, when the output voltage set by the step-down power supply is higher than the input voltage, for example, when the output voltage set by the power supply powered by 3-section lithium battery is 12V, the output voltage needs to be increased as much as possible to be close to the set output voltage, but the output voltage of the step-down power supply unit makes the bootstrap capacitor C1 unable to bootstrap charge, which results in that the upper bridge arm switching tube Q1 cannot set 100% duty ratio, and further results in the situation that the output voltage is far lower than the set output voltage.
Disclosure of Invention
The invention provides a voltage reduction power supply circuit structure, and aims to solve the problem that a bootstrap capacitor cannot be bootstrapped to charge when the input voltage of a voltage reduction power supply is lower than the set output voltage in the prior art, so that an upper bridge arm switching tube cannot set 100% duty ratio.
The embodiment of the invention is realized in such a way that a step-down power supply circuit structure comprises:
the voltage reduction output circuit is connected with the circuit input end, receives the voltage signal of the circuit input end and outputs a first voltage signal after voltage reduction;
the output driving circuit is connected with the output end of the voltage reduction output circuit and the input end of the circuit, and receives a first voltage signal to charge a bootstrap capacitor of the upper bridge arm switching tube;
the main control circuit is connected with the circuit input end, receives the voltage signal of the current input end and outputs an enabling control signal when the voltage signal of the circuit input end and a preset target voltage signal meet a preset first condition;
and the boost output circuit is connected with the output end of the main control circuit, the circuit input end and the output driving circuit and is used for boosting the voltage signal at the circuit input end and outputting the boosted voltage signal to the bootstrap capacitor for charging when receiving the enabling control signal, so that the switching tube of the upper bridge arm reaches the on state with 100% duty ratio.
Optionally, the step-down output circuit comprises a step-down power supply unit, a first resistor and a first diode;
the input end of the voltage reduction power supply unit is connected with the input end of the circuit, and the output end of the voltage reduction power supply unit is connected with one end of the first resistor;
the other end of the first resistor is connected with the anode of a first diode, and the cathode of the first diode is connected with the output drive circuit.
Optionally, the output end of the step-down power supply unit is further connected to the output driving circuit, and is configured to supply power to the output driving circuit.
Optionally, the output driving circuit includes a driving chip, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a bootstrap capacitor, a lower bridge arm switching tube and a lower bridge arm switching tube;
the driving chip comprises a chip voltage pin, a first input pin, a second input pin, a first control pin, a second control pin, a first output pin, a second output pin and a grounding pin;
the chip voltage end is connected with the first voltage end;
the first input pin and the second input pin are connected with an external driving signal end;
the first control pin is connected with the output end of the step-down output circuit and one end of the bootstrap capacitor;
the second control pin is connected with the other end of the bootstrap capacitor, one end of the second resistor, the first pole pin of the upper bridge arm switch tube, the third pole pin of the lower bridge arm switch tube and one end of the inductor, and the other end of the inductor is used as the output end of the voltage reduction power supply circuit structure;
the first output pin is connected with one end of the third resistor;
the second output pin is connected with one end of a fourth resistor;
a second-stage pin of the upper bridge arm switching tube is connected with the other end of the second resistor and the other end of the third resistor, and a third-stage pin is connected with the input end of the circuit;
the other end of the fourth resistor is connected with one end of the fifth resistor and a second-stage pin of the lower bridge arm switching tube;
and a first pole pin of the lower bridge arm switching tube, the other end of the fifth resistor and the grounding pin are grounded.
Optionally, the output driving circuit further includes a first capacitor, one end of the first capacitor is connected to the other end of the inductor, and the other end of the first capacitor is grounded.
Optionally, the lower bridge arm switching tube and the upper bridge arm switching tube are NMOS tubes.
Optionally, the main control circuit includes an input voltage detection unit and a control chip;
the input voltage detection unit is connected with the circuit input end and the control chip and is used for detecting a voltage signal of the circuit input end and outputting the voltage signal to the control chip;
the control chip is used for outputting an enabling control signal when the voltage signal at the input end of the circuit and the target voltage signal meet a first condition.
Optionally, the main control circuit further includes an output voltage detection unit;
the output voltage detection unit is connected with the output end of the voltage reduction power supply circuit structure and used for detecting a voltage signal output by the voltage reduction power supply circuit structure and feeding the voltage signal back to the control chip, so that the control chip calculates the duty ratio of the upper bridge arm switching tube according to the voltage signal at the circuit input end and the voltage signal output by the voltage reduction power supply circuit structure.
Optionally, the boost output circuit comprises a boost power supply unit and a second diode;
the input end of the boosting power supply unit is connected with the input end of the circuit, the enabling end of the boosting power supply unit is connected with the main control circuit, and the output end of the boosting power supply unit is connected with the anode of the second diode;
the cathode of the second diode is connected to the bootstrap capacitor.
In a second aspect, the present application further provides an electrical apparatus, including the step-down power supply circuit structure as described above.
In the embodiment of the invention, the voltage signal at the input end of the circuit is reduced by the voltage reduction output circuit to obtain the first voltage signal which is output to the output driving circuit to charge the bootstrap capacitor of the upper bridge arm switching tube, then the voltage signal of the circuit input end is detected by the main control circuit, when the voltage signal of the circuit input end is lower than the preset target voltage signal, determining that the voltage signal at the input end of the circuit and the target voltage signal meet a first condition, outputting an enable control signal to the boost output circuit by the main control circuit, boosting the voltage at the input end of the circuit by the boost output circuit and outputting the boosted voltage to the bootstrap capacitor for charging so that the bootstrap capacitor can be bootstrapped, the switching tube of the upper bridge arm is enabled to reach the on state of 100% duty ratio, the output voltage of the voltage reduction power supply circuit structure is improved to be close to or the same as the input voltage, and therefore the voltage drop between the input voltage and the output voltage is reduced as far as possible.
Drawings
FIG. 1 is a schematic diagram of a step-down power supply circuit of the prior art;
FIG. 2 is a circuit diagram of a buck power circuit configuration according to an embodiment of the present application;
fig. 3 is a circuit structure diagram of a step-down power supply circuit structure according to an embodiment of the present application
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
According to the embodiment of the application, the switching tube of the upper bridge arm can reach the on state with 100% duty ratio, the output voltage of the voltage reduction power supply circuit structure is improved to be close to or the same as the input voltage, and therefore the voltage drop between the input voltage and the output voltage is reduced as far as possible.
Example one
In some alternative embodiments, as shown in fig. 2 to 3, the present application provides a step-down power supply circuit structure, which includes a step-down output circuit 100, an output driving circuit 200, a main control circuit 300, and a step-up output circuit 400. The step-down output circuit 100 is connected to the circuit input terminal Vin, and the step-down output circuit 100 is configured to receive a voltage signal at the circuit input terminal Vin and output a first voltage signal after step-down; the output driving circuit 200 is connected with the output end of the step-down output circuit 100 and the circuit input end Vin, and receives a first voltage signal to charge a bootstrap capacitor C1 of the upper bridge arm switching tube Q1; the main control circuit 300 is connected with a circuit input end Vin, receives a voltage signal of the current input end Vin, and outputs an enable control signal when the voltage signal of the circuit input end Vin and a preset target voltage signal meet a preset first condition; the boost output circuit 400 is connected to the output end of the main control circuit 300, the circuit input end Vin, and the output driving circuit 200, and is configured to boost a voltage signal at the circuit input end Vin and output the boosted voltage signal to the bootstrap capacitor C1 for charging when receiving the enable control signal, so that the upper bridge arm switching tube Q1 reaches an on state with a duty ratio of 100%.
In implementation, the circuit input end Vin is an input end of the buck power supply circuit structure, a voltage signal of the circuit input end Vin is an input voltage of the buck power supply circuit structure, exemplarily, the voltage signal input by the circuit input end Vin includes 10V to 40V, and of course, the voltage signal of the circuit input end Vin may also be other voltage values, which is not limited herein.
The step-down output circuit 100 is configured to perform step-down processing on a voltage signal at an input terminal Vin of the circuit to obtain a first voltage signal, and output the first voltage signal to the output driving circuit 200, optionally, the output driving circuit 200 receives the first voltage signal to charge the bootstrap capacitor C1, in implementation, two NMOS transistors are generally used as switching tubes in the step-down power supply, and include an upper bridge arm switching tube Q1 and a lower bridge arm switching tube Q2, where a driving voltage of the upper bridge arm switching tube Q1 is from the bootstrap capacitor C1, when an input voltage of the step-down power supply is higher than a set output voltage, the first voltage signal output by the step-down output circuit 100 charges the bootstrap capacitor C1, a voltage of the bootstrap capacitor C1 may completely turn on the upper bridge arm switching tube Q1, for example, the case that the voltage signal input at the input terminal of the circuit includes 10V to 40V, when the output voltage set by the circuit structure of the step-down power supply of the present application is 12V, if the voltage at the input terminal Vin of the circuit is not less than 12V, for example, 15V, at this time, when the lower arm switch Q2 is turned on as a synchronous rectifier, the first voltage signal output by the step-down output circuit 100 bootstrap charges the bootstrap capacitor C1, so that the upper arm switch Q1 is fully turned on. When the voltage at the input terminal Vin of the circuit is less than 12V, for example, 10V, at this time, the first voltage signal output by the step-down output circuit 100 cannot bootstrap the bootstrap capacitor C1 for charging, so that the upper arm switch tube Q1 cannot be fully opened, that is, the upper arm switch tube Q1 cannot reach an on state of 100% duty ratio, for example, when the upper arm switch tube Q1 is in an on state of 50% duty ratio, the voltage output by the step-down power supply is 5V, which is much lower than the set 12V voltage.
When the main control circuit 300 detects that the voltage signal at the current input terminal Vin is lower than a preset target voltage signal, wherein the target voltage signal is the output voltage set by the step-down power supply, that is, when the input voltage of the step-down power supply is lower than the set output voltage, it is determined that the voltage signal at the current input terminal Vin and the target voltage signal satisfy the preset first condition, at this time, the main control circuit 300 outputs an enable control signal to the step-up output circuit 400, and when receiving the enable control signal, the step-up output circuit 400 performs step-up processing on the voltage signal at the circuit input terminal Vin and outputs the voltage signal to the bootstrap capacitor C1, by adding a voltage signal to the bootstrap capacitor C1, the bootstrap capacitor C1 can be bootstrapped, and the upper bridge arm switching tube Q1 reaches the on state of 100% duty ratio, and the voltage output by the step-down power supply is 10V at the moment, so that the output voltage is increased as much as possible to be close to the set 12V voltage.
In the embodiment of the invention, a voltage signal at a circuit input end Vin is reduced by a voltage reduction output circuit 100 to obtain a first voltage signal, the first voltage signal is output to an output driving circuit 200 to charge a bootstrap capacitor C1 of an upper bridge arm switching tube Q1, then the voltage signal at the circuit input end Vin is detected by a main control circuit 300, when the voltage signal at the circuit input end Vin is lower than a preset target voltage signal, it is determined that the voltage signal at the circuit input end Vin and the target voltage signal meet a first condition, at the moment, the main control circuit 300 outputs an enable control signal to a voltage boosting output circuit 400, the voltage at the circuit input end Vin is boosted by the voltage boosting output circuit 400 and then output to a bootstrap capacitor C1 for charging, so that the bootstrap capacitor C1 can be bootstrapped to enable an upper bridge arm switching tube Q1 to reach an on state with 100% duty ratio, the output voltage of a voltage reduction power supply circuit structure is increased to be close to or equal to the input voltage, thereby reducing the voltage drop between the input and output voltages as much as possible.
Example two
Alternatively, the step-down output circuit 100 includes a step-down power supply unit 110, a first resistor R1, and a first diode D1;
the input end of the voltage reduction power supply unit 110 is connected with the circuit input end Vin, and the output end of the voltage reduction power supply unit 110 is connected with one end of the first resistor R1;
the other end of the first resistor R1 is connected to the anode of the first diode D1, and the cathode of the first diode D1 is connected to the output driver circuit 200.
Optionally, the output driving circuit 200 includes a driving chip U1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a bootstrap capacitor C1, a lower bridge arm switching tube Q2, and a lower bridge arm switching tube Q1;
the driving chip U1 comprises a chip voltage pin VCC, a first input pin HIN, a second input pin LIN, a first control pin VB, a second control pin VS, a first output pin HO, a second output pin LO and a grounding pin COM;
the chip voltage end VCC is connected with the first voltage end Vcc;
the first input pin HIN and the second input pin LIN are connected with an external drive signal end;
the first control pin VB is connected to the output terminal of the step-down output circuit 100 and one end of the bootstrap capacitor C1;
the second control pin VS is connected with the other end of the bootstrap capacitor C2, one end of the second resistor R2, the first pole pin of the upper arm switch tube Q1, the third pole pin of the lower arm switch tube Q2 and one end of the inductor L1, and the other end of the inductor L1 is used as the output end Vout of the buck power supply circuit structure;
the first output pin HO is connected with one end of a third resistor R3;
the second output pin LO is connected to one end of the fourth resistor R4;
a second-stage pin of the upper bridge arm switching tube Q1 is connected with the other end of the second resistor R2 and the other end of the third resistor R3, and a third-stage pin of the upper bridge arm switching tube Q1 is connected with the circuit input end Vin;
the other end of the fourth resistor R4 is connected with one end of the fifth resistor R5 and a second-stage pin of the lower bridge arm switching tube Q2;
the first pole pin of the lower bridge arm switching tube Q2, the other end of the fifth resistor R5 and the ground pin COM are grounded.
In implementation, the BUCK power supply unit 110 may adopt a BUCK topology or other BUCK transformers, which is not limited herein.
Optionally, the driving chip U1 may adopt a single chip microcomputer, wherein the first voltage terminal Vcc is used to supply power to the driving chip U1, and in some optional embodiments, the output terminal of the step-down power supply unit 100 may further be connected to a chip voltage terminal Vcc of the driving chip U1, for supplying power to the driving chip U1.
Optionally, the first input pin HIN and the second input pin LIN of the driver chip U1 are configured to receive a PWM signal input from an external driving signal terminal, so that the driver chip U1 controls the on/off of the upper arm switch tube Q1 and the lower arm switch tube Q2 according to the PWM signal.
Optionally, the first control pin VB is connected to the cathode of the first diode D1 and one end of the bootstrap capacitor C1.
Optionally, the lower arm switch Q2 and the lower arm switch Q1 are NMOS transistors, and the first pole pin, the second pole pin, and the third pole pin of the switch are the source, the gate, and the drain of the MOS transistor, respectively.
Optionally, the output driving circuit 200 further includes a first capacitor C2, one end of the first capacitor C2 is connected to the other end of the inductor L1, and the other end of the first capacitor C2 is grounded.
In implementation, the stability of the output voltage signal of the voltage reduction power supply can be effectively improved by arranging the first capacitor C2.
Optionally, the main control circuit 300 includes an input voltage detection unit 310 and a control chip U2;
the input voltage detecting unit 310 is connected to the circuit input terminal Vin and the control chip U2, and is configured to detect a voltage signal at the circuit input terminal Vin and output the voltage signal to the control chip U2;
the control chip U2 is used for outputting an enable control signal when the voltage signal at the input terminal Vin of the circuit and the target voltage signal satisfy a first condition.
Alternatively, the control chip U2 includes a first input Vi1 and an enable output Vo, wherein the first input Vi1 is connected to the output terminal of the input voltage detecting unit 310, and the enable output Vo is connected to the boost output circuit 400.
Optionally, the main control circuit 300 further includes an output voltage detection unit 320;
the output voltage detection unit 320 is connected to the output end of the buck power supply circuit structure, and is configured to detect a voltage signal output by the buck power supply circuit structure and feed the voltage signal back to the control chip U2, so that the control chip U2 calculates the duty ratio of the upper bridge arm switching tube Q1 according to the voltage signal of the circuit input end Vin and the voltage signal output by the buck power supply circuit structure.
In implementation, the input end of the output voltage detection unit 320 is connected to the other end of the inductor L1, the output end of the output voltage detection unit 320 is connected to the second input end Vi2 of the control chip U2, the output voltage detection unit 320 detects the output voltage of the buck power supply and outputs the output voltage to the control chip U2, and the control chip U2 performs calculation according to the input voltage and the output voltage of the buck power supply to obtain the duty ratio of the upper arm switching tube Q1.
Alternatively, the boost output circuit 400 includes the boost power supply unit 410 and a second diode D2;
the input end of the boosting power supply unit 410 is connected with the circuit input end Vin, the enable end of the boosting power supply unit 410 is connected with the main control circuit 300, and the output end of the boosting power supply unit 410 is connected with the anode of the second diode D2;
the cathode of the second diode 2 is connected to a bootstrap capacitor C1.
When the voltage reduction power supply circuit is implemented, the enabling end of the voltage boosting power supply unit 410 is connected with the enabling output end Vo of the control chip U2, and the working principle of the voltage reduction power supply circuit structure is as follows:
firstly, the control chip U2 detects the input voltage (the voltage of the circuit input end Vin);
judging whether the input voltage is lower than the set output voltage, if the input voltage is not lower than the set output voltage, entering a PWM mode, and under the PWM mode, receiving and controlling the on-off of an upper bridge arm switching tube Q1 and a lower bridge arm switching tube Q2 by a driving chip U1 according to a PWM signal;
when the input voltage is lower than the set output voltage, the voltage signal output by the voltage reduction power supply unit 110 cannot enable the bootstrap capacitor C1 to be bootstrapped to charge, so that the upper bridge arm switching tube Q1 cannot be completely opened, at this time, the control chip U1 detects that the input voltage is lower than the set output voltage through the input voltage detection unit 310, the control chip U1 outputs an enable signal to the voltage boosting power supply unit 410, the voltage boosting power supply unit 410 works to output a voltage signal to the bootstrap capacitor C1, so that the bootstrap capacitor C1 can be bootstrapped to charge to completely open the upper bridge arm switching tube Q1, and the lower bridge arm switching tube Q2 is closed;
fourthly, the control chip U2 continuously outputs an enable signal to maintain the boosting power supply unit 410 to work, so that the upper bridge arm switching tube Q2 is continuously and completely opened; continuously detecting the input voltage and comparing the input voltage with the set output voltage;
and fifthly, continuously executing the steps until the input voltage is higher than the set output voltage, turning off the voltage power supply unit 410, and entering a PWM mode.
EXAMPLE III
In some optional embodiments, the present application further provides an electrical apparatus comprising the step-down power supply circuit structure as described above.
In implementation, the buck power circuit structure of the electrical apparatus includes a buck output circuit 100, an output driving circuit 200, a main control circuit 300, and a boost output circuit 400. The step-down output circuit 100 is connected to the circuit input terminal Vin, and the step-down output circuit 100 is configured to receive a voltage signal at the circuit input terminal Vin and output a first voltage signal after step-down; the output driving circuit 200 is connected with the output end of the step-down output circuit 100 and the circuit input end Vin, and receives a first voltage signal to charge a bootstrap capacitor C1 of the upper bridge arm switching tube Q1; the main control circuit 300 is connected with a circuit input end Vin, receives a voltage signal of the current input end Vin, and outputs an enable control signal when the voltage signal of the circuit input end Vin and a preset target voltage signal meet a preset first condition; the boost output circuit 400 is connected to the output end of the main control circuit 300, the circuit input end Vin, and the output driving circuit 200, and is configured to boost a voltage signal at the circuit input end Vin and output the boosted voltage signal to the bootstrap capacitor C1 to charge the bootstrap capacitor C1 when receiving an enable control signal, so that the upper bridge arm switching tube Q1 reaches an on state with a 100% duty ratio.
In implementation, the input end Vin of the circuit is an input end of the step-down power supply circuit structure, and optionally, the input end Vin of the circuit may be a power supply end of the electrical equipment, for example, if the electrical equipment uses three lithium batteries for power supply, the voltage of the input end Vin of the circuit is the sum of the voltages of the three lithium batteries.
The step-down output circuit 100 is configured to perform step-down processing on a voltage signal at an input end Vin of the circuit to obtain a first voltage signal, and output the first voltage signal to the output driving circuit 200, optionally, the output driving circuit 200 receives the first voltage signal to charge the bootstrap capacitor C1, in implementation, two NMOS transistors are generally used as switching tubes in the step-down power supply, and include an upper arm switching tube Q1 and a lower arm switching tube Q2, where a driving voltage of the upper arm switching tube Q1 is from the bootstrap capacitor C1, and when an input voltage of the step-down power supply is higher than a set output voltage, the first voltage signal output by the step-down output circuit 100 charges the bootstrap capacitor C1, and a voltage of the bootstrap capacitor C1 may completely open the upper arm switching tube Q1, for example, the voltage signal input at the input end Vin of the circuit includes 10V to 40V, and when the output voltage set by the structure of the step-down power supply of the present application is 12V, if the voltage at the input terminal Vin of the circuit is not less than 12V, for example, 15V, at this time, when the lower arm switch Q2 is turned on as a synchronous rectifier, the first voltage signal output by the step-down output circuit 100 bootstrap charges the bootstrap capacitor C1, so that the upper arm switch Q1 is fully turned on. When the voltage of the input end Vin of the circuit is less than 12V, for example, the sum of the voltages of the three lithium batteries is 10.5V, at this time, the first voltage signal output by the step-down output circuit 100 cannot bootstrap the bootstrap capacitor C1, so that the upper arm switching tube Q1 cannot be completely opened, that is, the upper arm switching tube Q1 cannot reach an on state with 100% duty ratio.
When the main control circuit 300 detects that the voltage signal at the current input terminal Vin is lower than a preset target voltage signal, wherein the target voltage signal is the output voltage set by the step-down power supply, that is, when the input voltage of the step-down power supply is lower than the set output voltage, it is determined that the voltage signal at the current input terminal Vin and the target voltage signal satisfy the preset first condition, at this time, the main control circuit 300 outputs an enable control signal to the step-up output circuit 400, and when receiving the enable control signal, the step-up output circuit 400 performs step-up processing on the voltage signal at the circuit input terminal Vin and outputs the voltage signal to the bootstrap capacitor C1, by adding a voltage signal to the bootstrap capacitor C1, the bootstrap capacitor C1 can be bootstrapped, and the upper bridge arm switching tube Q1 reaches the on state of 100% duty ratio, and the voltage output by the step-down power supply is 10V at the moment, so that the output voltage is increased as much as possible to be close to the set 12V voltage.
In the embodiment of the invention, a voltage signal at a circuit input end Vin is reduced by a voltage reduction output circuit 100 to obtain a first voltage signal, the first voltage signal is output to an output driving circuit 200 to charge a bootstrap capacitor C1 of an upper bridge arm switching tube Q1, then the voltage signal at the circuit input end Vin is detected by a main control circuit 300, when the voltage signal at the circuit input end Vin is lower than a preset target voltage signal, it is determined that the voltage signal at the circuit input end Vin and the target voltage signal meet a first condition, at the moment, the main control circuit 300 outputs an enable control signal to a voltage boosting output circuit 400, the voltage at the circuit input end Vin is boosted by the voltage boosting output circuit 400 and then output to a bootstrap capacitor C1 for charging, so that the bootstrap capacitor C1 can be bootstrapped to enable an upper bridge arm switching tube Q1 to reach an on state with 100% duty ratio, the output voltage of a voltage reduction power supply circuit structure is increased to be close to or equal to the input voltage, thereby reducing the voltage drop between the input and output voltages as much as possible.
The present invention is not limited to the above preferred embodiments, and any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. A step-down power supply circuit structure, comprising:
the voltage reduction output circuit is connected with the circuit input end, receives the voltage signal of the circuit input end and outputs a first voltage signal after voltage reduction;
the output driving circuit is connected with the output end of the voltage reduction output circuit and the input end of the circuit, and receives the first voltage signal to charge a bootstrap capacitor of the upper bridge arm switching tube;
the main control circuit is connected with the circuit input end, receives the voltage signal of the current input end and outputs an enabling control signal when the voltage signal of the circuit input end and a preset target voltage signal meet a preset first condition;
and the boost output circuit is connected with the output end of the main control circuit, the circuit input end and the output driving circuit, and is used for boosting the voltage signal at the circuit input end and outputting the boosted voltage signal to the bootstrap capacitor for charging when receiving the enabling control signal, so that the upper bridge arm switching tube reaches a switching-on state with 100% duty ratio.
2. The step-down power supply circuit structure according to claim 1, wherein the step-down output circuit includes a step-down power supply unit, a first resistor, and a first diode;
the input end of the voltage reduction power supply unit is connected with the input end of the circuit, and the output end of the voltage reduction power supply unit is connected with one end of the first resistor;
the other end of the first resistor is connected with the anode of the first diode, and the cathode of the first diode is connected with the output driving circuit.
3. The step-down power supply circuit structure of claim 2, wherein the output terminal of the step-down power supply unit is further connected to the output driving circuit for supplying power to the output driving circuit.
4. The buck power supply circuit structure according to claim 1, wherein the output driving circuit includes a driving chip, a second resistor, a third resistor, a fourth resistor, a fifth resistor, the bootstrap capacitor, a lower bridge arm switching tube and the lower bridge arm switching tube;
the driving chip comprises a chip voltage pin, a first input pin, a second input pin, a first control pin, a second control pin, a first output pin, a second output pin and a grounding pin;
the chip voltage end is connected with the first voltage end;
the first input pin and the second input pin are connected with an external driving signal end;
the first control pin is connected with the output end of the step-down output circuit and one end of the bootstrap capacitor;
the second control pin is connected with the other end of the bootstrap capacitor, one end of the second resistor, the first pole pin of the upper bridge arm switch tube, the third pole pin of the lower bridge arm switch tube and one end of an inductor, and the other end of the inductor is used as the output end of the step-down power supply circuit structure;
the first output pin is connected with one end of the third resistor;
the second output pin is connected with one end of the fourth resistor;
a second-stage pin of the upper bridge arm switching tube is connected with the other end of the second resistor and the other end of the third resistor, and a third-stage pin is connected with the input end of the circuit;
the other end of the fourth resistor is connected with one end of the fifth resistor and a second-stage pin of the lower bridge arm switching tube;
and a first pole pin of the lower bridge arm switching tube, the other end of the fifth resistor and the grounding pin are grounded.
5. The step-down power supply circuit structure according to claim 4, wherein the output driving circuit further comprises a first capacitor, one end of the first capacitor is connected to the other end of the inductor, and the other end of the first capacitor is grounded.
6. The buck power supply circuit structure according to claim 4 or 5, wherein the lower bridge arm switching tubes and the upper bridge arm switching tubes are NMOS tubes.
7. The step-down power supply circuit structure of claim 1, wherein the main control circuit comprises an input voltage detection unit and a control chip;
the input voltage detection unit is connected with the circuit input end and the control chip and is used for detecting a voltage signal of the circuit input end and outputting the voltage signal to the control chip;
the control chip is used for outputting the enabling control signal when the voltage signal of the circuit input end and the target voltage signal meet the first condition.
8. The step-down power supply circuit structure of claim 7, wherein the main control circuit further comprises an output voltage detection unit;
the output voltage detection unit is connected with the output end of the voltage reduction power supply circuit structure and used for detecting a voltage signal output by the voltage reduction power supply circuit structure and feeding the voltage signal back to the control chip, so that the control chip calculates the duty ratio of the upper bridge arm switching tube according to the voltage signal at the circuit input end and the voltage signal output by the voltage reduction power supply circuit structure.
9. The step-down power supply circuit configuration according to claim 1, wherein the step-up output circuit includes a step-up power supply unit and a second diode;
the input end of the boosting power supply unit is connected with the input end of the circuit, the enabling end of the boosting power supply unit is connected with the main control circuit, and the output end of the boosting power supply unit is connected with the anode of the second diode;
the cathode of the second diode is connected to the bootstrap capacitor.
10. A step-down power supply comprising the step-down power supply circuit configuration according to any one of claims 1 to 9.
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| CN202210439082.4A CN114744874A (en) | 2022-04-25 | 2022-04-25 | Step-down power supply circuit structure and step-down power supply |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115903976A (en) * | 2022-11-01 | 2023-04-04 | 广州鸿博微电子技术有限公司 | Method, device and equipment for controlling power consumption of digital integrated circuit and storage medium |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115903976A (en) * | 2022-11-01 | 2023-04-04 | 广州鸿博微电子技术有限公司 | Method, device and equipment for controlling power consumption of digital integrated circuit and storage medium |
| CN115903976B (en) * | 2022-11-01 | 2023-10-27 | 广州鸿博微电子技术有限公司 | Digital integrated circuit power consumption control method, device, equipment and storage medium |
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