CN217769877U - Power supply circuit controlled by PFM (pulse frequency modulation) mode and electronic equipment - Google Patents
Power supply circuit controlled by PFM (pulse frequency modulation) mode and electronic equipment Download PDFInfo
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- CN217769877U CN217769877U CN202221199436.4U CN202221199436U CN217769877U CN 217769877 U CN217769877 U CN 217769877U CN 202221199436 U CN202221199436 U CN 202221199436U CN 217769877 U CN217769877 U CN 217769877U
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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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Abstract
The utility model discloses a power supply circuit and electronic equipment of PFM mode control, undervoltage protection circuit's first end is connected with power input end, control chip's undervoltage protection pin is connected with undervoltage protection circuit's second end, peak current sets up the first end of circuit and is connected with control chip's peak current pin, switching frequency selection circuit's first end is connected with control chip's external oscillation frequency control pin, chip power supply filter circuit's first end is connected with control chip's DC power supply pin, chip power supply filter circuit's second end sets up the second end of circuit with peak current respectively, switching frequency selection circuit's second end and undervoltage protection circuit's third end are connected, voltage transformation circuit's first end, control chip's power pin is connected with power input end, voltage transformation circuit's second end is connected with control chip's energy conversion pin. The technical problem of high no-load power consumption is solved.
Description
Technical Field
The utility model relates to a power supply circuit technical field, in particular to power supply circuit and electronic equipment of PFM mode control.
Background
Electronic equipment such as airborne equipment, missile-borne equipment, naval vessel inside needs miniwatt power module, has used a plurality of power modules in the same system, requires that power module efficiency is high, and no-load static loss is little, accords with the little requirement of environmental protection stand-by power consumption, uses traditional PWM chip mode, and it is big to have no-load current, and complete machine inefficiency. The no-load power consumption accounts for 10% -20% of the total power, and the efficiency of the whole machine can only reach 60% -75%.
SUMMERY OF THE UTILITY MODEL
An object of the utility model is to provide a power supply circuit and electronic equipment of PFM mode control for solve the higher technical problem of no-load consumption.
In order to achieve the above object, the present invention provides a power circuit controlled by PFM mode, which comprises:
the power supply input end is used for accessing a power supply;
a ground terminal;
a power supply output terminal;
the undervoltage protection circuit is provided with a first end, a second end and a third end, wherein the first end of the undervoltage protection circuit is connected with the power supply input end and is used for detecting working voltage;
the control chip is provided with a power supply pin, an under-voltage protection pin, an external oscillation frequency control pin, a peak current pin, a direct current power supply pin, a grounding pin and an energy conversion pin, wherein the power supply pin of the control chip is connected with the power supply input end, the under-voltage protection pin of the control chip is connected with the second end of the under-voltage protection circuit, and the grounding pin of the control chip is connected with the grounding end;
the first end of the peak current setting circuit is connected with a peak current pin of the control chip;
the first end of the switching frequency selection circuit is connected with an external oscillation frequency control pin of the control chip;
a first end of the chip power supply filter circuit is connected with a direct-current power supply pin of the control chip, and a second end of the chip power supply filter circuit is respectively connected with a second end of the peak current setting circuit, a second end of the switching frequency selection circuit and a third end of the under-voltage protection circuit;
the first end of the voltage transformation circuit is connected with the power supply input end, and the second end of the voltage transformation circuit is connected with the energy conversion pin of the control chip and is used for converting the power supply voltage and outputting the converted power supply voltage through the power supply output end;
the control chip is used for entering a PWM mode when the working voltage is larger than a preset voltage value; or the like, or a combination thereof,
and when the working voltage is less than or equal to a preset voltage value and/or when the working current is greater than a preset current value, entering a PFM mode.
Optionally, the under-voltage protection circuit includes a first resistor, a second resistor, and a third resistor, a first end of the first resistor is a first end of the under-voltage protection circuit, and a second end of the first resistor is connected to a first end of the second resistor; the second end of the second resistor is connected with the first end of the third resistor, and the connection node of the second resistor is the second end of the undervoltage protection circuit; and the second end of the third resistor is the third end of the undervoltage protection circuit.
Optionally, the peak current setting circuit includes a fourth resistor, a first end of the fourth resistor is a first end of the peak current setting circuit, and a second end of the fourth resistor is a second end of the peak current setting circuit.
Optionally, the switching frequency selection circuit includes a fifth resistor, a first end of the fifth resistor is a first end of the switching frequency selection circuit, and a second end of the fifth resistor is a second end of the switching frequency selection circuit.
Optionally, the PFM mode controlled power supply circuit further includes an input filter circuit, and the input filter circuit is disposed between the power supply input terminal and the output terminal.
Optionally, the PFM mode-controlled power circuit further includes a backflow prevention circuit, an input end of the backflow prevention circuit is connected to the power input end, and an output end of the backflow prevention circuit is connected to a power supply end of the control chip.
Optionally, the PFM mode-controlled power supply circuit further includes an output rectifying circuit and a pi-type filter circuit, the pi-type filter circuit includes an input terminal, an output terminal, and a ground terminal, the transformer circuit further has a first output terminal and a second output terminal, the first output terminal of the transformer circuit is connected to the input terminal of the output rectifying circuit, and the second output terminal of the transformer circuit is connected to the ground terminal of the pi-type filter circuit; the input end of the pi-type filter circuit is connected with the output end of the output rectifying circuit, and the output end of the pi-type filter circuit is grounded.
Optionally, the output rectification circuit includes a second diode, an anode of the second diode is an input end of the output rectification circuit, and a cathode of the second diode is an output end of the output rectification circuit.
Optionally, the pi-type filter circuit includes a third capacitor, a fourth capacitor, and a first inductor, a first end of the fourth capacitor is connected to a first end of the first inductor, a connection node of the fourth capacitor is an input end of the pi-type filter circuit, a first end of the third capacitor and a second end of the fourth capacitor are both grounded, a second end of the third capacitor is connected to a second end of the first inductor, and a connection node of the third capacitor is an output end of the pi-type filter circuit.
In order to achieve the above object, the present invention further provides an electronic device, which includes the PFM mode controlled power supply circuit as described above.
The utility model provides a power supply circuit and electronic equipment of PFM mode control, the undervoltage protection circuit detects operating voltage, and control chip enters PWM mode when the operating voltage is greater than the preset voltage value; or when the working voltage is less than or equal to a preset voltage value and/or the working current is greater than a preset current value, entering a PFM mode; therefore, when the voltage and/or the current are/is smaller, namely the load is smaller, the control chip can enter a PFM mode with lower power consumption, and the technical problem of higher no-load power consumption is solved.
Drawings
The present invention will be further described with reference to the accompanying drawings and examples;
fig. 1 is a circuit diagram of a PFM mode controlled power supply circuit according to an embodiment.
Detailed Description
This section will describe in detail the embodiments of the present invention, preferred embodiments of the present invention are shown in the attached drawings, which are used to supplement the description of the text part of the specification with figures, so that one can intuitively and vividly understand each technical feature and the whole technical solution of the present invention, but they cannot be understood as the limitation of the protection scope of the present invention.
The utility model provides a power supply circuit of PFM mode control for solve the higher technical problem of no-load power consumption.
In an embodiment, as shown in fig. 1, the PFM mode controlled power circuit includes a power input terminal, a ground terminal, a power output terminal, an under-voltage protection circuit, a control chip U3 having a PWM mode and a PFM mode, a peak current setting circuit, a switching frequency selection circuit, a chip power filter circuit, and a transformer circuit, the under-voltage protection circuit has a first terminal, a second terminal, and a third terminal, the first terminal of the under-voltage protection circuit is connected to the power input terminal; the control chip U3 is provided with a power supply pin 1, an under-voltage protection pin 2, an external oscillation frequency control pin 3, a peak current pin 4, a direct current power supply pin 5, grounding pins (6, 7 and 8) and energy conversion pins (9, 10 and 11), the power supply pin of the control chip U3 is connected with the power supply input end, the under-voltage protection pin of the control chip U3 is connected with the second end of the under-voltage protection circuit, and the grounding pin of the control chip U3 is connected with the grounding end; the first end of the peak current setting circuit is connected with a peak current pin of the control chip U3; the first end of the switching frequency selection circuit is connected with an external oscillation frequency control pin of the control chip U3; a first end of the chip power supply filter circuit is connected with a direct-current power supply pin of the control chip U3, and a second end of the chip power supply filter circuit is respectively connected with a second end of the peak current setting circuit, a second end of the switching frequency selection circuit and a third end of the undervoltage protection circuit; the first end of the voltage transformation circuit is connected with the power input end, and the second end of the voltage transformation circuit is connected with the energy conversion pin of the control chip U3.
Wherein, the power input end is connected with a power supply; the undervoltage protection circuit detects a working voltage, and the control chip U3 enters a PWM mode when the working voltage is larger than a preset voltage value; or entering a PFM mode when the working voltage is less than or equal to a preset voltage value and/or the working current is greater than a preset current value. The voltage transformation circuit converts the power supply voltage and outputs the converted power supply voltage through the power supply output end, so that the control chip U3 can enter a PFM mode with lower power consumption when the voltage is lower and/or the current is higher, namely the load is lower, and the technical problem of higher no-load power consumption is solved. In addition, the peak current setting circuit may set a peak current that can be output by the transformer circuit, and the switching frequency selection circuit may set a switching frequency of a switching tube built in the control chip U3. The chip power supply filter circuit filters the power supply voltage input into the chip.
Optionally, the transformer circuit includes a transformer T1, and the selection of the transformer may be performed as needed.
Optionally, the chip power filter circuit includes a second capacitor C2.
Optionally, the under-voltage protection circuit includes a first resistor R1, a second resistor R2, and a third resistor R3, where a first end of the first resistor R1 is a first end of the under-voltage protection circuit, and a second end of the first resistor R1 is connected to a first end of the second resistor R2; the second end of the second resistor R2 is connected to the first end of the third resistor R3, and the connection node thereof is the second end of the under-voltage protection circuit; and the second end of the third resistor R3 is the third end of the undervoltage protection circuit.
The first resistor R1, the second resistor R2 and the third resistor R3 can reasonably divide voltage, and the detected working voltage is guaranteed to be in a safety range when being input to the control chip U3. And can trigger the under-voltage protection.
Optionally, the peak current setting circuit includes a fourth resistor R4, a first end of the fourth resistor R4 is a first end of the peak current setting circuit, and a second end of the fourth resistor R4 is a second end of the peak current setting circuit.
Wherein the peak current can be varied by selecting the resistance of the fourth resistor R4.
Optionally, the switching frequency selection circuit includes a fifth resistor R5, a first end of the fifth resistor R5 is a first end of the switching frequency selection circuit, and a second end of the fifth resistor R5 is a second end of the switching frequency selection circuit.
The switching frequency of the switching tube arranged inside the control chip U3 can be changed by selecting the resistance value of the fifth resistor R5.
Optionally, the PFM mode controlled power supply circuit further includes an input filter circuit, and the input filter circuit is disposed between the power supply input terminal and the output terminal.
The input filter circuit filters the power supply, and it should be noted that the input filter circuit is composed of a first capacitor. The withstand voltage of the capacitor can be selected according to the power supply voltage.
Optionally, the power circuit controlled by the PFM mode further includes a backflow prevention circuit, an input end of the backflow prevention circuit is connected to the power input end, and an output end of the backflow prevention circuit is connected to a power supply end of the control chip U3.
At this time, the backflow prevention circuit can prevent the current direction from flowing backwards to damage the control chip U3. Optionally, the backflow prevention circuit is implemented by a first diode D1.
Optionally, the PFM mode-controlled power supply circuit further includes an output rectifying circuit and a pi-type filter circuit, the pi-type filter circuit includes an input terminal, an output terminal, and a ground terminal, the transformer circuit further has a first output terminal and a second output terminal, the first output terminal of the transformer circuit is connected to the input terminal of the output rectifying circuit, and the second output terminal of the transformer circuit is connected to the ground terminal of the pi-type filter circuit; the input end of the pi-type filter circuit is connected with the output end of the output rectifying circuit, and the output end of the pi-type filter circuit is grounded.
Optionally, the output rectification circuit includes a second diode D2, an anode of the second diode D2 is an input end of the output rectification circuit, and a cathode of the second diode D2 is an output end of the output rectification circuit.
Optionally, the pi-type filter circuit includes a third capacitor C3, a fourth capacitor C4 and a first inductor L1, a first end of the fourth capacitor C4 is connected to a first end of the first inductor L1, a connection node of the fourth capacitor C4 is an input end of the pi-type filter circuit, a first end of the third capacitor C3 and a second end of the fourth capacitor are both grounded, a second end of the third capacitor C3 is connected to a second end of the first inductor L1, and a connection node of the third capacitor C3 is an output end of the pi-type filter circuit.
The working principle of the present invention is explained with reference to fig. 1 as follows:
c1 is an input filter capacitor, the withstand voltage value of the capacitor can be selected according to input voltage, and the capacity value of the capacitor can be selected according to output power. And the R1, the R2 and the R3 form an input undervoltage protection circuit. R4 determines the switching frequency through the resistance. R5 determines the output overcurrent point of the product through the resistance. And C2 is a filter capacitor of VCC. D1 is a backflow prevention diode. D2 is an output rectifier diode. C3, C4 and L1 form pi-type filtering. The chip U3 is a main control chip U3, and a 120V/4A power MOS tube is integrated in the chip, so that the size of the whole module can be reduced. The product is internally provided with a lossless peak current sampling circuit, and the peak current can be set through R5. The chip can work in a CCM (continuous conduction Mode) Mode and a DCM (discontinuous conduction Mode), the DCM is set corresponding to the PFM Mode, and the simulation frequency reduction is carried out when the chip is in light load or no load so as to improve the efficiency and reduce the no-load power consumption. With the reduction of the load of the switching power supply, the voltage VEA is also gradually reduced, the working frequency starts to be reduced with the reduction of the voltage VEA when the load is reduced to about 30 percent of the maximum output power, and the minimum switching frequency Fmin is limited when the load is extremely light, so that the minimum load is limited to avoid the output voltage from being floated, the circuit can achieve the effect that the no-load power consumption accounts for within 3 percent of the total power, and the efficiency of the whole machine can reach more than 83 percent.
When the PFM mode control chip U3 is adopted, the voltage at two ends of the current detection resistor is reduced when the product is in a no-load or light-load state, the working frequency is reduced along with the reduction of the load when the load is reduced to about 30 percent of the maximum output power, and is reduced to 7KHz at the minimum, so that the no-load power consumption is reduced, and the PFM mode control chip U3 has the functions of environmental protection and energy conservation. Under the full load state, the PWM mode state is entered, and the frequency can be set to 100 KHz-700 KHz. The requirements of low power consumption and high efficiency are met. The scheme is mainly different from the traditional PWM chip, and adopts a PWM mode in a full-load state and a PFM mode in a light-load state. Based on the peripheral circuit of the U3 chip, the output overcurrent and light load are regulated through R5 to enter a PFM mode.
The utility model also provides an electronic equipment, electronic equipment includes the power supply circuit of PFM mode control as above.
It should be noted that, since the electronic device of the present application includes all the schemes of the power supply circuit controlled in the PFM mode, the electronic device may also implement all the schemes of the power supply circuit controlled in the PFM mode, and has the same beneficial effects, and details are not described herein again.
The technical features of the above embodiments can be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the above embodiments are not described, but should be considered as the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
Claims (10)
1. A PFM mode controlled power supply circuit, comprising:
the power supply input end is used for accessing a power supply;
a ground terminal;
a power supply output terminal;
the undervoltage protection circuit is provided with a first end, a second end and a third end, wherein the first end of the undervoltage protection circuit is connected with the power input end and used for detecting working voltage;
the control chip is provided with a power supply pin, an under-voltage protection pin, an external oscillation frequency control pin, a peak current pin, a direct current power supply pin, a grounding pin and an energy conversion pin, wherein the power supply pin of the control chip is connected with the power supply input end, the under-voltage protection pin of the control chip is connected with the second end of the under-voltage protection circuit, and the grounding pin of the control chip is connected with the grounding end;
the first end of the peak current setting circuit is connected with a peak current pin of the control chip and used for detecting working current;
the first end of the switching frequency selection circuit is connected with an external oscillation frequency control pin of the control chip;
a first end of the chip power supply filter circuit is connected with a direct-current power supply pin of the control chip, and a second end of the chip power supply filter circuit is respectively connected with a second end of the peak current setting circuit, a second end of the switching frequency selection circuit and a third end of the under-voltage protection circuit;
the first end of the voltage transformation circuit is connected with the power supply input end, and the second end of the voltage transformation circuit is connected with the energy conversion pin of the control chip and is used for converting the power supply voltage and outputting the converted power supply voltage through the power supply output end;
the control chip is used for entering a PWM mode when the working voltage is larger than a preset voltage value; or the like, or, alternatively,
and when the working voltage is less than or equal to a preset voltage value and/or when the working current is greater than a preset current value, entering a PFM mode.
2. The PFM mode controlled power supply circuit of claim 1, wherein the under-voltage protection circuit comprises a first resistor, a second resistor and a third resistor, a first end of the first resistor is a first end of the under-voltage protection circuit, and a second end of the first resistor is connected to a first end of the second resistor; the second end of the second resistor is connected with the first end of the third resistor, and the connection node of the second resistor is the second end of the undervoltage protection circuit; and the second end of the third resistor is the third end of the undervoltage protection circuit.
3. The PFM mode controlled power supply circuit of claim 1, wherein said peak current setting circuit comprises a fourth resistor, a first terminal of said fourth resistor being a first terminal of said peak current setting circuit, a second terminal of said fourth resistor being a second terminal of said peak current setting circuit.
4. The PFM mode controlled power supply circuit of claim 1, wherein said switching frequency selection circuit comprises a fifth resistor, a first terminal of said fifth resistor being a first terminal of said switching frequency selection circuit, a second terminal of said fifth resistor being a second terminal of said switching frequency selection circuit.
5. The PFM mode controlled power supply circuit of claim 1, further comprising an input filter circuit disposed between said power supply input terminal and an output terminal.
6. The PFM mode controlled power supply circuit of claim 1, further comprising a back-flow prevention circuit, wherein an input terminal of said back-flow prevention circuit is connected to said power input terminal, and an output terminal of said back-flow prevention circuit is connected to a power supply terminal of said control chip.
7. The PFM mode controlled power supply circuit of claim 1, further comprising an output rectifying circuit and a pi-type filter circuit, wherein the pi-type filter circuit comprises an input terminal, an output terminal, and a ground terminal, wherein the transformer circuit further has a first output terminal and a second output terminal, wherein the first output terminal of the transformer circuit is connected to the input terminal of the output rectifying circuit, and the second output terminal of the transformer circuit is connected to the ground terminal of the pi-type filter circuit; the input end of the pi-type filter circuit is connected with the output end of the output rectifying circuit, and the output end of the pi-type filter circuit is grounded.
8. The PFM mode controlled power supply circuit of claim 7, wherein said output rectifying circuit comprises a second diode, an anode of said second diode being an input terminal of said output rectifying circuit, and a cathode of said second diode being an output terminal of said output rectifying circuit.
9. The PFM mode controlled power supply circuit of claim 8, wherein said pi filter circuit comprises a third capacitor, a fourth capacitor and a first inductor, a first terminal of said fourth capacitor is connected to a first terminal of said first inductor, a connection node thereof is an input terminal of said pi filter circuit, a first terminal of said third capacitor and a second terminal of said fourth capacitor are both grounded, a second terminal of said third capacitor is connected to a second terminal of said first inductor, and a connection node thereof is an output terminal of said pi filter circuit.
10. An electronic device characterized in that the electronic device comprises the PFM mode controlled power supply circuit according to any one of claims 1 to 8.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202221199436.4U CN217769877U (en) | 2022-05-17 | 2022-05-17 | Power supply circuit controlled by PFM (pulse frequency modulation) mode and electronic equipment |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202221199436.4U CN217769877U (en) | 2022-05-17 | 2022-05-17 | Power supply circuit controlled by PFM (pulse frequency modulation) mode and electronic equipment |
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| Publication Number | Publication Date |
|---|---|
| CN217769877U true CN217769877U (en) | 2022-11-08 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202221199436.4U Active CN217769877U (en) | 2022-05-17 | 2022-05-17 | Power supply circuit controlled by PFM (pulse frequency modulation) mode and electronic equipment |
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| CN (1) | CN217769877U (en) |
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- 2022-05-17 CN CN202221199436.4U patent/CN217769877U/en active Active
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