CN216981797U - Feedback circuit of chip - Google Patents
Feedback circuit of chip Download PDFInfo
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- CN216981797U CN216981797U CN202220363557.1U CN202220363557U CN216981797U CN 216981797 U CN216981797 U CN 216981797U CN 202220363557 U CN202220363557 U CN 202220363557U CN 216981797 U CN216981797 U CN 216981797U
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Abstract
The utility model provides a feedback circuit of a chip, comprising: the technical scheme includes that the switch module is connected with a chip through the compensation module, so that the adjustment precision is greatly improved, the output voltage is close to an ideal value after adjustment, two compensation modules are added, different parameters correspond to different response speeds, a circuit can be adjusted stably and quickly, the phenomenon of over-adjustment or under-adjustment is not easy to occur, and finally the voltage tends to be stable.
Description
Technical Field
The utility model relates to the technical field of chips, in particular to a feedback circuit of a chip.
Background
Feedback circuit of chip uses the opto-coupler to feed back usually among the prior art, perhaps adopts the VFB foot lug connection resistance of chip to carry out the sampling to output (being altogether), uses the opto-coupler can lead to product cost too high, and carries out the sampling feedback from chip VFB foot lug connection resistance to the output, leads to the precision relatively poor, and the regulation response is slow.
SUMMERY OF THE UTILITY MODEL
The utility model aims to provide a feedback circuit of a chip, which aims to solve the problems of high cost caused by adopting an optical coupler and poor precision and slow regulation response caused by adopting a chip connecting resistor to carry out sampling feedback to an output end in the prior art.
A first aspect of the present invention provides a feedback circuit of a chip, the feedback circuit including:
a fourth winding of the transformer is connected with a sixth pin of the chip;
a first end of the sixth resistor is connected with the fourth winding of the transformer;
the cathode of the voltage stabilizing tube is connected with the second end of the sixth resistor;
a fifth resistor, the first end of which is connected with the cathode of the voltage regulator tube, and the second end of which is grounded;
the first end of the first compensation module is connected with the anode of the voltage stabilizing tube;
the control end of the switch module is connected with the anode of the voltage regulator tube, the input end of the switch module is connected with the second end of the first compensation module and the second pin of the chip, and the output end of the switch module is grounded;
the first end of the second compensation module is connected with the second end of the first compensation module, and the second end of the second compensation module is grounded;
a second end of the seventh resistor is connected with the fourth winding of the transformer, and a first end of the seventh resistor is connected with the first pin of the chip;
a first end of the fourth resistor is connected with the second end of the seventh resistor, and a second end of the fourth resistor is grounded;
the grid electrode of the NMOS tube is connected with the fifth pin of the chip, the drain electrode of the NMOS tube is connected with the second winding of the transformer, and the source electrode of the NMOS tube is connected with the third pin of the chip;
a first end of the fourth capacitor is connected with the sixth pin of the chip, and a second end of the fourth capacitor is grounded;
and the first end of the eighth resistor is connected with the source electrode of the NMOS tube, and the second end of the eighth resistor is grounded.
Further, the first compensation module includes a resistor R1 and a capacitor C1, a first end of the resistor R1 is a first end of the first compensation module, a second end of the resistor R1 is connected to a first end of the capacitor C1, and a second end of the capacitor C1 is a second end of the first compensation module.
Further, the second compensation module includes a resistor R3 and a capacitor C3, a first end of the capacitor C3 is a first end of the second compensation module, a second end of the capacitor C3 is connected to a first end of the resistor R3, and a second end of the resistor R3 is a second end of the second compensation module.
Furthermore, the switch module is a triode, the base of the triode is the control end of the switch module, the collector of the triode is the input end of the switch module, and the emitter of the triode is the output end of the switch module.
Further, the model of the chip is NCP 1377.
Furthermore, the feedback circuit further comprises a resistor R2, a first end of the resistor R2 is connected to the base of the transistor, and a second end of the resistor R2 is grounded.
The present embodiment provides a feedback circuit of a chip, including: the technical scheme includes that the switch module is connected with a chip through the compensation module, so that the adjustment precision is greatly improved, the output voltage is close to an ideal value after adjustment, two compensation modules are added, different parameters correspond to different response speeds, a circuit can be adjusted stably and quickly, the phenomenon of over-adjustment or under-adjustment is not easy to occur, and finally the voltage tends to be stable.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the embodiments or the prior art descriptions will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive exercise.
Fig. 1 is a circuit diagram of a feedback circuit of a chip according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further 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 utility model and are not intended to limit the utility model.
In order to explain the technical means of the present invention, the following description will be given by way of specific examples.
An embodiment of the present invention provides a feedback circuit of a chip, and as shown in fig. 1, the feedback circuit includes:
a fourth winding of the transformer M is connected with a sixth pin of the chip;
a sixth resistor R6, a first end of which is connected to the fourth winding of the transformer M;
a voltage regulator tube Z1, the cathode of which is connected with the second end of the sixth resistor R6;
a fifth resistor R5, the first end of which is connected with the cathode of the voltage regulator tube Z1, and the second end of which is grounded;
a first end of the first compensation module 11 is connected with an anode of a voltage regulator tube Z1;
a control end of the switch module Q1 is connected with the anode of the voltage regulator tube Z1, an input end of the switch module Q1 is connected with the second end of the first compensation module 11 and the second pin of the chip, and an output end of the switch module Q1 is grounded;
a second compensation module 12, a first end of which is connected to the second end of the first compensation module 11, and a second end of which is grounded;
a second end of the seventh resistor R7 is connected with the fourth winding of the transformer M, and a first end of the seventh resistor R7 is connected with the first pin of the chip;
a first end of the fourth resistor R4 is connected to the second end of the seventh resistor R7, and a second end thereof is grounded;
the grid electrode of the NMOS tube Q2 is connected with the fifth pin of the chip, the drain electrode of the NMOS tube Q2 is connected with the second winding of the transformer M, and the source electrode of the NMOS tube Q2 is connected with the third pin of the chip;
a first end of the fourth capacitor C4 is connected with the sixth pin of the chip, and a second end of the fourth capacitor C4 is grounded;
the first end of the eighth resistor R8 is connected to the source of the NMOS transistor Q2, and the second end is grounded.
The model of the chip is NCP1377, pin 1 of the chip is demagnetization and OVP detection pin, pin 2 is feedback pin, pin 3 CS current detection pin, pin 4 and pin 5 are ground connection and drive signal pin respectively, and pin 6 and pin 8 are VCC power supply and high voltage pin respectively.
The switching module Q1 is a triode, the base of the triode is the control end of the switching module, the collector of the triode is the input end of the switching module, and the emitter of the triode is the output end of the switching module.
The feedback circuit further comprises a resistor R2, a first end of the resistor R2 is connected with a base electrode of the triode, and a second end of the resistor R2 is grounded. The resistor R2 is a biasing resistor of the transistor.
The fourth winding of the transformer M is connected with a diode D1, the feedback module 10 samples the voltage after diode rectification through the third winding 3 and the fourth winding 4 of the transformer M, as shown in point a in fig. 1, the sampled voltage obtains a divided voltage value through a fifth resistor R5 and a sixth resistor R6 of a voltage dividing network, the voltage value generates a minute current through a voltage regulator tube Z1 and a BE electrode of the triode, so that the triode works in an amplification state, and the minute current is a base current Ib of the triode.
The first compensation module comprises a resistor R1 and a capacitor C1, a first end of the resistor R1 is a first end of the first compensation module, a second end of the resistor R1 is connected with a first end of the capacitor C1, and a second end of the capacitor C1 is a second end of the first compensation module. For adjusting the response time of the circuit.
The second compensation module comprises a resistor R3 and a capacitor C3, a first end of the capacitor C3 is a first end of the second compensation module, a second end of the capacitor C3 is connected with a first end of the resistor R3, and a second end of the resistor R3 is a second end of the second compensation module. For adjusting the response time of the circuit.
The first compensation module comprises a chip IRF7240, a first pin of the chip IRF7240 is a first end of the first compensation module, the first pin of the chip IRF7240 is respectively connected with a cathode of a first diode, a cathode of a second diode, a positive electrode of a first polarity capacitor, a No. 2 pin and a No. 3 pin of the chip IRF7240, and a cathode of the second diode is respectively connected with a ground resistor, a cathode of the first polarity capacitor and a No. 4 pin of the chip IRF 7240; the anode of the first diode is grounded; chip IRF 7240's 5 th pin is connected rather than 6 th pin, 7 th pin and 8 th pin respectively, and chip IRF 7240's 8 th pin is the second end of first compensation module, and chip IRF 7240's 8 th pin is connected with the one end of ground capacitance, the positive pole of third polar capacitance and tenth resistance respectively, and the other end of fourth resistance is connected with emitting diode's positive pole, and the negative pole ground connection of third polar capacitance, emitting diode's negative pole ground connection.
In the embodiment, in order to reduce the impact of the power supply voltage at the moment of plugging and unplugging when the feedback circuit is made into a plugging and unplugging module, the protection can be realized by overhigh voltage.
The working principle of the circuit structure is as follows: when the circuit is switched to a light load working state in a full load working state, the voltage at the point A is slightly increased in a short time, the voltage of the cathode of the voltage regulator tube Z1 is increased, the current flowing through the voltage regulator tube Z1 is correspondingly increased, namely the base current Ib of the triode Q1 is increased, the collector current Ic of the triode Q1 is also correspondingly increased according to Ic Ib beta, at the moment, the voltage VFB of the pin 2 of the chip is pulled down, and the chip adjusts the driving duty ratio after detecting that the voltage of the VFB is reduced, so that the voltage at the point A returns to a normal value. For the NCP1377 chip, there is a 4.2V pull-up voltage inside the FB pin.
Similarly, when the circuit is switched from a light-load working state to a full-load working state, the voltage at the point A is slightly reduced in a short time, the voltage of the cathode of the voltage regulator tube Z1 is reduced, the current flowing through the voltage regulator tube Z1 is correspondingly reduced, namely the base current Ib of the triode Q1 is reduced, the collector current Ic of the triode Q1 is also correspondingly reduced according to the condition that Ic is Ib beta, the voltage VFB of the pin 2 of the chip is raised at the moment, and the chip adjusts the driving duty ratio after detecting that the voltage of the VFB is increased, so that the voltage at the point A returns to a normal value.
The present embodiment provides a feedback circuit of a chip, including: the technical scheme includes that the switch module is connected with the chip through the compensation module, so that the adjustment precision is greatly improved, the output voltage after adjustment is close to an ideal value, the two compensation modules are added, different parameters correspond to different response speeds, a circuit can be stably and quickly adjusted, the phenomenon of overshoot or undershoot is not prone to occurring, and finally the voltage tends to a stable level.
The foregoing is a more detailed description of the utility model in connection with specific preferred embodiments and it is not intended that the utility model be limited to these specific details. For those skilled in the art to which the utility model pertains, several equivalent substitutions or obvious modifications, which are equivalent in performance or use, without departing from the inventive concept, should be considered as falling within the scope of the present invention as defined by the appended claims.
Claims (6)
1. A feedback circuit of a chip, comprising: the feedback circuit includes:
a fourth winding of the transformer is connected with a sixth pin of the chip;
a first end of the sixth resistor is connected with the fourth winding of the transformer;
the cathode of the voltage stabilizing tube is connected with the second end of the sixth resistor;
a fifth resistor, the first end of which is connected with the cathode of the voltage regulator tube, and the second end of which is grounded;
the first end of the first compensation module is connected with the anode of the voltage stabilizing tube;
the control end of the switch module is connected with the anode of the voltage regulator tube, the input end of the switch module is connected with the second end of the first compensation module and the second pin of the chip, and the output end of the switch module is grounded;
the first end of the second compensation module is connected with the second end of the first compensation module, and the second end of the second compensation module is grounded;
a second end of the seventh resistor is connected with the fourth winding of the transformer, and a first end of the seventh resistor is connected with the first pin of the chip;
a first end of the fourth resistor is connected with the second end of the seventh resistor, and a second end of the fourth resistor is grounded;
the grid electrode of the NMOS tube is connected with the fifth pin of the chip, the drain electrode of the NMOS tube is connected with the second winding of the transformer, and the source electrode of the NMOS tube is connected with the third pin of the chip;
a first end of the fourth capacitor is connected with the sixth pin of the chip, and a second end of the fourth capacitor is grounded;
and the first end of the eighth resistor is connected with the source electrode of the NMOS tube, and the second end of the eighth resistor is grounded.
2. The feedback circuit as claimed in claim 1, wherein the first compensation module comprises a resistor R1 and a capacitor C1, wherein a first terminal of the resistor R1 is a first terminal of the first compensation module, a second terminal of the resistor R1 is connected to a first terminal of a capacitor C1, and a second terminal of the capacitor C1 is a second terminal of the first compensation module.
3. The feedback circuit as claimed in claim 1, wherein the second compensation module comprises a resistor R3 and a capacitor C3, a first terminal of the capacitor C3 is a first terminal of the second compensation module, a second terminal of the capacitor C3 is connected to a first terminal of the resistor R3, and a second terminal of the resistor R3 is a second terminal of the second compensation module.
4. The feedback circuit of claim 1 wherein the switching module is a transistor, a base of the transistor is a control terminal of the switching module, a collector of the transistor is an input terminal of the switching module, and an emitter of the transistor is an output terminal of the switching module.
5. The feedback circuit of claim 1, wherein the chip is model number NCP 1377.
6. The feedback circuit as claimed in claim 4, wherein the feedback circuit further comprises a resistor R2, a first terminal of the resistor R2 is connected to the base of the transistor, and a second terminal of the resistor R2 is connected to ground.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202220363557.1U CN216981797U (en) | 2022-02-22 | 2022-02-22 | Feedback circuit of chip |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202220363557.1U CN216981797U (en) | 2022-02-22 | 2022-02-22 | Feedback circuit of chip |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN216981797U true CN216981797U (en) | 2022-07-15 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202220363557.1U Active CN216981797U (en) | 2022-02-22 | 2022-02-22 | Feedback circuit of chip |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN216981797U (en) |
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2022
- 2022-02-22 CN CN202220363557.1U patent/CN216981797U/en active Active
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