CN211044052U - Voltage stabilizing circuit - Google Patents
Voltage stabilizing circuit Download PDFInfo
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- CN211044052U CN211044052U CN201922296544.8U CN201922296544U CN211044052U CN 211044052 U CN211044052 U CN 211044052U CN 201922296544 U CN201922296544 U CN 201922296544U CN 211044052 U CN211044052 U CN 211044052U
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Abstract
The utility model provides a voltage stabilizing circuit, the input and the input power positive electricity of P-MOS module are connected, and the output and the input electricity of voltage stabilizing module of P-MOS module are connected, and voltage stabilizing module's output is connected with the input electricity of amplifying the module, and the output of amplifying the module is connected with drive module's input electricity, and drive module's output is connected with the drive end electricity of P-MOS module, and input power negative connection is referenced ground. The voltage stabilizing circuit has the advantages of low loss and high precision, and can sense the change of input voltage in real time, when the input voltage is lower, the P-MOS module is conducted, the conduction internal resistance of the P-MOS module is very small at the moment, and the loss of the P-MOS module is very low; when the input voltage is higher, the rear-stage voltage stabilizing circuit, the amplifying circuit and the driving circuit start to work, at the moment, the P-MOS module works in the variable resistance area, and the voltage between the grid electrode and the source electrode of the P-MOS module is adjusted timely, so that the aim of stabilizing the output voltage is fulfilled.
Description
Technical Field
The utility model relates to a voltage stabilizing circuit, in particular to voltage stabilizing circuit when flyback converter multiplexed output unbalance loading.
Background
The flyback converter has the advantages of simple circuit structure, primary side excitation and secondary side demagnetization of the transformer during operation, high utilization rate of the magnetic core and no demagnetization winding, so that the flyback converter has the advantages of small volume, low cost and good dynamic response, and is widely applied to occasions with high voltage and small current, multipath output and input and output needing electrical isolation.
However, when the flyback converter is applied to multi-path output offset load, the main circuit output voltage is used as a feedback input end, the output voltage precision is high, and when the main circuit is fully loaded, the auxiliary circuit is lightly loaded or unloaded, the auxiliary circuit output voltage is high due to asymmetric leakage inductance, or when the main circuit is fully loaded, the auxiliary circuit voltage is low, so that the precision of the auxiliary circuit output voltage is poor, the fluctuation is large, and the load is possibly damaged.
The output voltage of the winding without feedback has a large variation range due to asymmetric secondary side leakage inductance, and the load is easily damaged. Although the prior art uses a three-terminal regulator to stabilize output voltage, when the load is large, the power consumption of the three-terminal regulator is large, the requirement of high efficiency is not met, and the three-terminal regulator is only suitable for small current application occasions. The prior art also has a technology for stabilizing the output voltage by using an IC chip, and although the technology can make the precision of the output voltage higher, the peripheral devices of the IC chip increase the cost and the volume, and bring about serious EMI problems.
SUMMERY OF THE UTILITY MODEL
In view of this, the utility model provides a be applied to voltage stabilizing circuit of flyback converter with multiplexed output solves present voltage stabilizing circuit precision not high and the great defect of loss.
The utility model discloses a realize through following technical scheme:
a voltage stabilizing circuit comprises a P-MOS module, a driving module, an amplifying module and a voltage stabilizing module; the P-MOS module is used for adjusting the output voltage, the driving module is used for controlling the working state of the P-MOS module, the amplifying module is used for amplifying a fluctuation signal of the output voltage, and the voltage stabilizing module is used for stabilizing the output voltage; the connection relationship is as follows: the input end of the P-MOS module is connected with the positive electricity of an input power supply, the output end of the P-MOS module is electrically connected with the input end of the voltage stabilizing module, the output end of the voltage stabilizing module is electrically connected with the input end of the amplifying module, the output end of the amplifying module is electrically connected with the input end of the driving module, the output end of the driving module is electrically connected with the driving end of the P-MOS module, and the input power supply is negatively connected with the reference ground.
As a specific embodiment of the above P-MOS module, the P-MOS module includes a P-MOS transistor, a first drying capacitor, and a second drying capacitor; the source electrode of the P-MOS tube is used as the input end of the P-MOS module, the grid electrode of the P-MOS tube is used as the output end of the P-MOS module, the drain electrode of the P-MOS tube is used as the driving end of the P-MOS module, the first drying capacitor is connected between the source electrode and the drain electrode of the P-MOS tube in parallel and used for filtering noise interference between the source electrode and the grid electrode of the P-MOS tube, and the second drying capacitor is connected between the grid electrode and the drain electrode of the P-MOS tube in parallel and used for filtering noise interference between the grid electrode and the drain electrode of the P-MOS tube.
As a specific implementation manner of the voltage stabilizing module, the voltage stabilizing module includes a voltage stabilizing diode, a current limiting resistor and a reference resistor; the cathode of the voltage stabilizing diode is used as the input end of the voltage stabilizing module, the anode of the voltage stabilizing diode is connected with one end of the current limiting resistor, the other end of the current limiting resistor is connected with one end of the reference resistor, the connection point of the current limiting resistor is used as the output end of the voltage stabilizing module, and the other end of the reference resistor is connected with the reference ground.
As a specific implementation manner of the above amplifying module, the amplifying module includes an NPN transistor, a first bias resistor, a second bias resistor, and a PNP transistor; an emitting electrode of the PNP triode and one end of the second biasing resistor are connected with an input power supply, a base electrode of the NPN triode is used as an input end of the amplification module, voltage at two ends of the reference resistor is used as a base electrode power supply of the NPN triode, a collecting electrode of the NPN triode is connected with one end of the first biasing resistor, the other end of the first biasing resistor is connected with the other end of the second biasing resistor, a connecting point of the first biasing resistor is connected with a base electrode of the PNP triode, an emitting electrode of the NPN triode is connected with a reference ground, and a collecting.
As a specific implementation manner of the driving module, the driving module includes a first voltage-dividing resistor and a second voltage-dividing resistor, one end of the first voltage-dividing resistor is used as an input end of the driving module, the other end of the first voltage-dividing resistor and one end of the second voltage-dividing resistor are connected to be used as an output end of the driving module, the other end of the second voltage-dividing resistor is connected to a reference ground, and the first voltage-dividing resistor and the second voltage-dividing resistor divide a signal output by the PNP triode to be used as a gate power supply of the P-MOS transistor, so as to adjust a potential difference between a source and a gate of the P-MOS transistor.
The utility model discloses a voltage stabilizing circuit is applied to flyback converter with multiplexed output, flyback converter includes input circuit, transformer and output circuit, and output circuit includes main output circuit and the auxiliary output circuit of at least all the way, and auxiliary output circuit's positive output end is just as voltage stabilizing circuit's input power supply, and auxiliary output circuit's negative output end connects the reference ground as input power supply burden, and its theory of operation is as follows:
when the main circuit output circuit outputs light load and the auxiliary circuit output circuit outputs heavy load or full load, the output voltage of the auxiliary circuit output circuit is low after being rectified by the rectifier diode, the P-MOS tube is conducted, and the P-MOS tube is conducted due to internal resistance RdsonThe voltage regulator circuit is very small, and the conduction voltage drop is small, so that the output voltage of the voltage regulator circuit can be approximately equal to the output voltage of the auxiliary circuit output circuit; when the voltage of the voltage stabilizing module, namely the sum of the voltage drops of the voltage stabilizing diode, the current limiting resistor and the reference resistor, is greater than the output voltage of the voltage stabilizing circuit, the voltage stabilizing module and the amplifying module do not work, and the NPN triode is not conducted, so that the drain electrode potential of the P-MOS module is 0, the P-MOS tube is completely conducted, the output voltage is the auxiliary circuit output voltage of the flyback converter minus the conduction voltage of the P-MOS tube, and the loss of the corresponding P-MOS tube is I0 2*RdsonAnd RdsonAnd the conduction loss of the P-MOS transistor is small, and is generally in the milliohm level.
When the output of the main circuit output circuit is heavy load or full load and the output of the auxiliary circuit output circuit is light load, the output voltage of the auxiliary circuit output circuit is higher after being rectified by the diode, the source electrode potential of the P-MOS module is increased, and the P-MOS module is completely conducted; when the output voltage of the voltage stabilizing circuit rises to conduct the voltage stabilizing diode, the voltage stabilizing circuit starts to work, when the voltage at two ends of the reference resistor reaches 0.7V, the NPN triode is conducted, and at the moment, the conducted voltage drop Vce of the NPN triode and the terminal voltage values of the first bias resistor and the second bias resistor are equal toThe output voltage of the auxiliary circuit output circuit is equal to the source electrode potential of the P-MOS tube; when the values of the first bias resistor and the second bias resistor are reasonable, and the terminal voltage of the second bias resistor reaches 0.7V, the PNP triode is conducted, and at the moment, the conduction voltage drop Vec of the PNP triode plus the terminal voltages of the first voltage dividing resistor and the second voltage dividing resistor is equal to the output voltage of the auxiliary circuit output circuit, namely the source electrode potential of the P-MOS tube; when the values of the first voltage-dividing resistor and the second voltage-dividing resistor are reasonable, due to the voltage-dividing effect of the first voltage-dividing resistor and the second voltage-dividing resistor, the potential of the second voltage-dividing resistor is increased, namely the drain potential of the P-MOS tube is increased, the relative potential difference of the drain and the source of the P-MOS tube is reduced at the moment, the gate and the source of the P-MOS tube are not completely conducted, the P-MOS tube works in a variable resistance area, the voltage difference Vsd between the gates of the P-MOS tube is increased, the output voltage of the voltage stabilizing circuit is equal to the voltage obtained by subtracting the voltage between the gate and the source of the P-MOS tube from the source voltage of the P-MOS tube, and therefore the output voltage of the voltage stabilizing circuit is reduced, the output voltage of the voltage stabilizing. The loss of the corresponding P-MOS tube is (V)S-VD)*I0When the auxiliary road is lightly loaded, I0The loss of the P-MOS tube is very small; the first denoising capacitor is used for filtering noise interference between the source grid electrodes of the P-MOS module, and the second denoising capacitor is used for filtering noise interference between the drain electrodes of the grid electrodes of the P-MOS module.
Compared with the prior art, the utility model have following advantage and beneficial effect:
(1) the loss is low: when the input voltage is lower, the P-MOS module is completely conducted, and the loss of the P-MOS module is I0 2*Rdson；
(2) The voltage stabilization precision is high: when the input voltage is higher, the back-stage voltage stabilizing circuit starts to work, and the conduction state of the P-MOS module is adjusted timely according to the change of the input voltage, so that the P-MOS module works in a variable resistance region, and the purpose of stabilizing the output voltage is achieved;
(3) the peripheral devices are few, the cost is low: the circuit structure is simple, and only one P-MOS module, one NPN triode, one PNP triode, one voltage stabilizing diode, six chip resistors and two chip capacitors are adopted;
(4) the reliability is higher: the number of used devices is small, and the reliability of the product is improved.
Drawings
FIG. 1 is a schematic block diagram of a voltage regulator circuit according to the present invention;
fig. 2 is a schematic diagram of the flyback converter to which the voltage stabilizing circuit of the present invention is applied.
Detailed Description
FIG. 1 is a schematic block diagram of a voltage regulator circuit according to the present embodiment, where the circuit includes: the P-MOS module 200, the driving module 400, the amplifying module 500 and the voltage stabilizing module 600; the input end of the P-MOS module 200 is connected with the positive Vin + of the input power supply, the output end of the P-MOS module is electrically connected with the input end of the voltage stabilizing module 600, the output end of the voltage stabilizing module 600 is electrically connected with the input end of the amplifying module 500, the power supply end of the amplifying module 500 is connected with the positive Vin-of the input power supply, the output end of the amplifying module 500 is electrically connected with the input end of the driving module 400, the output end of the driving module 400 is electrically connected with the driving end of the P-MOS module 200, and the grounding ends of all the modules.
Fig. 2 is the utility model discloses a voltage stabilizing circuit is applied to flyback converter's schematic diagram, as shown in the figure, flyback converter includes input circuit, transformer and output circuit, and output circuit includes main output circuit and the auxiliary output circuit of the same kind, and auxiliary output circuit is input module 100 promptly, and auxiliary output circuit's positive output is as input power supply positive Vin +, auxiliary output circuit's negative output is as input power supply negative Vin-, resistance R is load module 300 promptly. The components and the connection relation of each module are as follows:
the P-MOS module comprises a P-MOS tube 201, a first drying capacitor 201 and a second drying capacitor 202, wherein the source electrode of the P-MOS tube 203 is connected with the positive output end of the auxiliary circuit output circuit, the grid electrode of the P-MOS tube 203 is connected with one end of a resistor R, the drain electrode of the P-MOS tube 203 is used as the driving end of the P-MOS module 200, the first drying capacitor 201 is connected in parallel with the two ends of the source electrode and the drain electrode of the P-MOS tube 203 and used for filtering noise interference between the source electrode and the grid electrode of the P-MOS tube 203, and the second drying capacitor 202 is connected in parallel with the two ends of the grid electrode and the drain electrode of the P-MOS tube 203 and used for filtering noise interference between the grid electrode and the drain electrode of the P-MOS.
The voltage stabilizing module 600 comprises a voltage stabilizing diode 601, a current limiting resistor 602 and a reference resistor 603, wherein the cathode of the voltage stabilizing diode 601 is connected with the gate of the P-MOS transistor 203, the anode of the voltage stabilizing diode 601 is connected with one end of the current limiting resistor 602, the other end of the current limiting resistor 602 is connected with one end of the reference resistor 603, and the other end of the reference resistor 603 is connected with the negative output end of the auxiliary circuit output circuit.
The amplifying module 500 comprises an NPN triode 501, a first biasing resistor 502, a second biasing resistor 503 and a PNP triode 504, wherein the base of the NPN triode 501 is connected between the current limiting resistor 602 and the reference resistor 603, the voltage at the two ends of the reference resistor 603 is used as the base power supply of the NPN triode, the collector of the NPN triode 501 is connected with one end of the first biasing resistor 502, the other end of the first biasing resistor 502 is connected with one end of the second biasing resistor 503 and the base of the PNP triode 504, the other end of the biasing resistor 503 is connected with the emitter of the PNP triode 504 and is connected with the positive output end of the auxiliary output circuit, and the emitter of the NPN triode 501 is connected with the negative output end of the auxiliary output circuit; the NPN transistor 501 is used in an amplification area during operation, and the PNP transistor 504 is used for amplifying a signal of the NPN transistor 501 and outputting the signal to the driving module 400.
The driving module 400 includes a first voltage-dividing resistor 401 and a second voltage-dividing resistor 402, wherein one end of the first voltage-dividing resistor 401 is connected to the collector of the PNP transistor 504, one end of the second voltage-dividing resistor 402 is connected to the reference ground, the other end of the first voltage-dividing resistor 401 and the other end of the second voltage-dividing resistor 402 are connected to the driving terminal of the P-MOS module, the first voltage-dividing resistor 401 and the second voltage-dividing resistor 402 divide the voltage of the signal output by the PNP transistor 504 to serve as the gate power supply of the P-MOS transistor 203, and the potential difference between the source and the gate of the P-MOS transistor 203 is adjusted.
The voltage stabilizing circuit of the embodiment is applied to a flyback converter with multiple outputs, and the specific working process can be briefly described as follows:
when the output voltage of the auxiliary circuit output circuit is low, the P-MOS module 200 is completely turned on, the voltage stabilizing circuit 600 and the amplifying circuit 500 at the rear stage do not work, and the conduction loss of the P-MOS module 200 is small.
When the output voltage of the auxiliary circuit output circuit is higher, the P-MOS module 200 works in the variable resistance region, and the small change of the voltage of the rear-stage load module 300 is amplified by the voltage stabilizing circuit 600 and the amplifying circuit 500, so that the driving voltage of the driving module 400 is changed, the conducting state of the P-MOS module 200 is changed, at this time, the P-MOS module 200 works in the variable resistance region, the output voltage of the voltage stabilizing circuit is equal to the output voltage of the auxiliary circuit output circuit minus the voltage between the source and the drain of the P-MOS module 200, the purpose of stabilizing the output voltage is achieved, and meanwhile, the loss of the P-MOS module 200 is small.
The above is only the preferred embodiment of the present invention, and it should be noted that the above preferred embodiment should not be considered as the limitation of the present invention, the protection scope of the present invention should be limited by the scope defined by the claims, and for those skilled in the art, several modifications and decorations can be made without departing from the spirit and scope of the present invention, and these modifications and decorations should also be considered as the protection scope of the present invention.
Claims (5)
1. A voltage stabilizing circuit is characterized in that: the device comprises a P-MOS module, a driving module, an amplifying module and a voltage stabilizing module; the connection relationship is as follows: the input end of the P-MOS module is connected with the positive electricity of an input power supply, the output end of the P-MOS module is electrically connected with the input end of the voltage stabilizing module, the output end of the voltage stabilizing module is electrically connected with the input end of the amplifying module, the output end of the amplifying module is electrically connected with the input end of the driving module, the output end of the driving module is electrically connected with the driving end of the P-MOS module, and the input power supply is negatively connected with the reference ground.
2. The voltage regulator circuit of claim 1, wherein: the P-MOS module comprises a P-MOS tube, a first drying capacitor and a second drying capacitor; the source electrode of the P-MOS tube is used as the input end of the P-MOS module, the grid electrode of the P-MOS tube is used as the output end of the P-MOS module, the drain electrode of the P-MOS tube is used as the driving end of the P-MOS module, the first drying capacitor is connected between the source electrode and the drain electrode of the P-MOS tube in parallel, and the second drying capacitor is connected between the grid electrode and the drain electrode of the P-MOS tube in parallel.
3. The voltage regulator circuit of claim 1, wherein the voltage regulator module comprises a zener diode, a current limiting resistor, and a reference resistor; the cathode of the voltage stabilizing diode is used as the input end of the voltage stabilizing module, the anode of the voltage stabilizing diode is connected with one end of the current limiting resistor, the other end of the current limiting resistor is connected with one end of the reference resistor, the connection point of the current limiting resistor is used as the output end of the voltage stabilizing module, and the other end of the reference resistor is connected with the reference ground.
4. The voltage stabilizing circuit according to claim 1, wherein the amplifying module comprises an NPN transistor, a first bias resistor, a second bias resistor, and a PNP transistor; an emitting electrode of the PNP triode and one end of the second biasing resistor are connected with the positive input power supply, a base electrode of the NPN triode is used as the input end of the amplification module, a collecting electrode of the NPN triode is connected with one end of the first biasing resistor, the other end of the first biasing resistor is connected with the other end of the second biasing resistor, a connecting point of the first biasing resistor and the second biasing resistor is connected with the base electrode of the PNP triode, the emitting electrode of the NPN triode is connected with the reference ground, and the collecting electrode of the PN.
5. The voltage regulator circuit of claim 1, wherein: the driving module comprises a first voltage-dividing resistor and a second voltage-dividing resistor, one end of the first voltage-dividing resistor is used as an input end of the driving module, the other end of the first voltage-dividing resistor and one end of the second voltage-dividing resistor are connected to be used as an output end of the driving module, and the other end of the second voltage-dividing resistor is connected to a reference ground.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201922296544.8U CN211044052U (en) | 2019-12-19 | 2019-12-19 | Voltage stabilizing circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201922296544.8U CN211044052U (en) | 2019-12-19 | 2019-12-19 | Voltage stabilizing circuit |
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| Publication Number | Publication Date |
|---|---|
| CN211044052U true CN211044052U (en) | 2020-07-17 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201922296544.8U Active CN211044052U (en) | 2019-12-19 | 2019-12-19 | Voltage stabilizing circuit |
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|---|---|
| CN (1) | CN211044052U (en) |
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- 2019-12-19 CN CN201922296544.8U patent/CN211044052U/en active Active
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