CN109640494B - Overload protection and short circuit restorable PWM light modulator - Google Patents
Overload protection and short circuit restorable PWM light modulator Download PDFInfo
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- CN109640494B CN109640494B CN201910076030.3A CN201910076030A CN109640494B CN 109640494 B CN109640494 B CN 109640494B CN 201910076030 A CN201910076030 A CN 201910076030A CN 109640494 B CN109640494 B CN 109640494B
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- 238000001514 detection method Methods 0.000 claims abstract description 10
- 230000002265 prevention Effects 0.000 claims abstract description 9
- 238000005070 sampling Methods 0.000 claims description 22
- 239000003990 capacitor Substances 0.000 claims description 10
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
Classifications
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B47/00—Circuit arrangements for operating light sources in general, i.e. where the type of light source is not relevant
- H05B47/10—Controlling the light source
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- Circuit Arrangement For Electric Light Sources In General (AREA)
- Dc-Dc Converters (AREA)
Abstract
The invention discloses an overload protection and short circuit restorable PWM dimmer, which comprises a PWM modulation circuit, an overcurrent detection circuit, an undervoltage protection circuit and an input/output reverse connection prevention protection circuit. The circuit structure of the invention has strong reliability and strong function, and can realize PWM modulation, overcurrent detection, VCC under-voltage protection and reverse connection prevention protection of input and output.
Description
Technical Field
The invention relates to the technical field of dimmers, in particular to an overload protection and short circuit restorable PWM dimmer.
Background
Dimmer refers to an electrical device that changes the luminous flux of a light source in a lighting device, adjusting the illuminance level. High capacity and constitutes a system called dimmer. The basic principle is to change the effective value of the current input to the light source to achieve the aim of dimming.
The current dimmer circuit has simple structure, poor stability, single function and unrecoverable output short circuit.
Disclosure of Invention
The technical problem to be solved by the invention is to provide an overload protection and short circuit recoverable PWM dimmer aiming at the defects of the prior art.
In order to solve the technical problems, the invention adopts the following technical scheme: an overload protection and short circuit restorable PWM dimmer comprises a PWM modulation circuit, an overcurrent detection circuit, an undervoltage protection circuit and an input/output reverse connection prevention protection circuit; the PWM modulation circuit comprises a driving chip U1 and a potentiometer CON3, and the duty ratio of PWM signals output by the driving chip U1 is adjusted in a knob potentiometer mode; the overcurrent detection circuit comprises a sampling resistor R6 connected in series at the dimming output end, the sampling resistor R6 is subjected to current sampling by the operational amplifier U2B, and the switch of the switching tube Q3 is controlled according to the output of the sampling current so as to control the on-off of the VCC input of the driving chip U1; the undervoltage protection circuit comprises an operational amplifier U2A, and the driving chip U1 drives the output of the operational amplifier U2A to fail a switching tube Q1 for controlling the on-off of the dimming output through a switching tube Q4 under the undervoltage state so as to stop the output; the driving chip U1 recovers the dimming output through the conduction of the switching tube Q1 in the state of recovering the VCC input; the input/output reverse connection prevention protection circuit comprises diodes which are respectively and electrically connected with the input end and the dimming output end.
In the above technical scheme, the input end of the switching tube Q4 is electrically connected with the control end of the switching tube Q1, the output end of the switching tube Q4 is grounded, the control end of the switching tube Q4 is electrically connected with the output end of the operational amplifier U2A, and the comparison input end VOL of the operational amplifier U2A is electrically connected with the FLT output end of the driving chip U1.
In the above technical scheme, the sampling resistor R6 IS connected to the output end of the switching tube Q1 and then grounded, the control end of the switching tube Q1 IS electrically connected with the DRV end of the driving chip U1, the output end of the switching tube Q1 IS electrically connected with the comparison input end IS of the operational amplifier U2B as a sampling node of the sampling resistor R6, the output end of the operational amplifier U2B IS electrically connected with the control end of the switching tube Q3, the input end of the switching tube Q3 IS electrically connected with the control end of the switching tube Q2, the input end of the switching tube Q2 IS electrically connected with the power source vin+, and the output end of the switching tube Q2 IS electrically connected with the power source input by VCC.
In the above technical scheme, a resistor R11 and a capacitor C6 are electrically connected between the switching tube Q2 and the power supply vin+.
In the above technical scheme, the VIN end of the driving chip U1 is electrically connected with the power supply input by VCC, and is electrically connected with the GND end, then grounded, and the VCC end of the driving chip U1 is connected with the negative electrode of the electrolytic capacitor C2 after terminating the capacitor C3.
The beneficial effects of the invention are as follows: the circuit structure has strong reliability and powerful functions, and can realize PWM modulation, overcurrent detection, VCC under-voltage protection and reverse connection prevention protection of input and output.
Drawings
Fig. 1 is a schematic view of the overall structure of the present invention.
Detailed Description
The invention is described in further detail below with reference to the accompanying drawings.
As shown in fig. 1, an overload protection and short circuit recoverable PWM dimmer comprises a PWM modulation circuit, an overcurrent detection circuit, an undervoltage protection circuit, and an input/output reverse connection prevention protection circuit; the PWM modulation circuit comprises a driving chip U1 and a potentiometer CON3, and the duty ratio of PWM signals output by the driving chip U1 is adjusted in a knob potentiometer mode; the overcurrent detection circuit comprises a sampling resistor R6 connected in series at the dimming output end, the sampling resistor R6 is subjected to current sampling by the operational amplifier U2B, and the switch of the switching tube Q3 is controlled according to the output of the sampling current so as to control the on-off of the VCC input of the driving chip U1; the undervoltage protection circuit comprises an operational amplifier U2A, and the driving chip U1 drives the output of the operational amplifier U2A to fail a switching tube Q1 for controlling the on-off of the dimming output through a switching tube Q4 under the undervoltage state so as to stop the output; the driving chip U1 recovers the dimming output through the conduction of the switching tube Q1 in the state of recovering the VCC input; the input/output reverse connection prevention protection circuit comprises diodes which are respectively and electrically connected with the input end and the dimming output end.
The input end of the switching tube Q4 is electrically connected with the control end of the switching tube Q1, the output end of the switching tube Q4 is grounded, the control end of the switching tube Q4 is electrically connected with the output end of the operational amplifier U2A, and the comparison input end VOL of the operational amplifier U2A is electrically connected with the FLT output end of the driving chip U1. The FLT output end of the driving chip U1 is electrically connected with a capacitor C4 for filtering.
The sampling resistor R6 IS grounded after being connected to the output end of the switching tube Q1, the control end of the switching tube Q1 IS electrically connected with the DRV end of the driving chip U1, the output end of the switching tube Q1 IS electrically connected with the comparison input end IS of the operational amplifier U2B as a sampling node of the sampling resistor R6, the output end of the operational amplifier U2B IS electrically connected with the control end of the switching tube Q3, the input end of the switching tube Q3 IS electrically connected with the control end of the switching tube Q2, the input end of the switching tube Q2 IS electrically connected with the power supply VIN+, and the output end of the switching tube Q2 IS electrically connected with the power supply input by VCC.
A resistor R11 and a capacitor C6 are electrically connected between the switching tube Q2 and the power source vin+.
The VIN end of the driving chip U1 is electrically connected with a power supply input by VCC, and is electrically connected with the GND end, then grounded, and the VCC end of the driving chip U1 is connected with the capacitor C3 and then connected with the cathode of the capacitor C2.
The working principle of the invention is as follows: the duty ratio of the PWM signal is changed by adjusting the potentiometer knob, so that the dimming function is realized. When the output is overloaded or shorted, the high level is output through the sampling resistor detection signal through the operational amplifier to close the VCC, so that the VCC is undervoltage, and meanwhile, the output MOSFET is rapidly turned off, so that overload and short-circuit protection functions are realized.
The foregoing examples are provided for the purpose of illustration only and are not intended to be limiting, and all equivalent changes or modifications made by the method described in the claims are intended to be included within the scope of the present invention.
Claims (5)
1. An overload protection and short circuit recoverable PWM dimmer, comprising: the device comprises a PWM (pulse width modulation) circuit, an overcurrent detection circuit, an undervoltage protection circuit and an input/output reverse connection prevention protection circuit; the PWM modulation circuit comprises a driving chip U1, a potentiometer CON3 and a resistor R3, wherein the dim end of the driving chip U1 is connected with the adjusting end of the potentiometer CON3, one end of the potentiometer CON3 is grounded through the resistor R3, and the duty ratio of PWM signals output by the driving chip U1 is adjusted in a knob potentiometer mode; the overcurrent detection circuit comprises a sampling resistor R6 connected in series with a dimming output end, one end of the sampling resistor R6 IS grounded, the other end of the sampling resistor R6 IS connected with a comparison input end IS of the operational amplifier U2B, the operational amplifier U2B samples current of the sampling resistor R6 and controls the switch of the switching tube Q3 according to the output of the sampled current so as to control the on-off of VCC input of the driving chip U1; the undervoltage protection circuit comprises an operational amplifier U2A, and a driving chip U1 drives the output of the operational amplifier U2A under the undervoltage state and disables a switching tube Q1 for controlling the on-off of the dimming output through a switching tube Q4 so as to stop the output; the driving chip U1 recovers the dimming output through the conduction of the switching tube Q1 in the state of recovering the VCC input; the input/output reverse connection prevention protection circuit comprises diodes which are respectively and electrically connected with the input end and the dimming output end.
2. The overload protection and short circuit restorable PWM dimmer according to claim 1, wherein: the input end of the switching tube Q4 is electrically connected with the control end of the switching tube Q1, the output end of the switching tube Q4 is grounded, the control end of the switching tube Q4 is electrically connected with the output end of the operational amplifier U2A, and the comparison input end VOL of the operational amplifier U2A is electrically connected with the FLT output end of the driving chip U1.
3. The overload protection and short circuit restorable PWM dimmer according to claim 1, wherein: the sampling resistor R6 IS connected to the output end of the switching tube Q1 and then grounded, the control end of the switching tube Q1 IS electrically connected with the DRV end of the driving chip U1, the output end of the switching tube Q1 IS electrically connected with the comparison input end IS of the operational amplifier U2B as a sampling node of the sampling resistor R6, the output end of the operational amplifier U2B IS electrically connected with the control end of the switching tube Q3, the input end of the switching tube Q3 IS electrically connected with the control end of the switching tube Q2, the input end of the switching tube Q2 IS electrically connected with the power supply VIN+, and the output end of the switching tube Q2 IS electrically connected with the power supply input by VCC.
4. An overload protection and short circuit restorable PWM dimmer according to claim 3, wherein: a resistor R11 and a capacitor C6 are electrically connected between the switching tube Q2 and the power supply vin+.
5. An overload protection and short circuit restorable PWM dimmer according to claim 1, wherein: the VIN end of the driving chip U1 is electrically connected with a power supply input by VCC, and is electrically connected with the GND end and then grounded, and the VCC end of the driving chip U1 is connected with the cathode of the electrolytic capacitor C2 after being connected with the capacitor C3.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910076030.3A CN109640494B (en) | 2019-01-26 | 2019-01-26 | Overload protection and short circuit restorable PWM light modulator |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910076030.3A CN109640494B (en) | 2019-01-26 | 2019-01-26 | Overload protection and short circuit restorable PWM light modulator |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN109640494A CN109640494A (en) | 2019-04-16 |
| CN109640494B true CN109640494B (en) | 2024-06-18 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201910076030.3A Active CN109640494B (en) | 2019-01-26 | 2019-01-26 | Overload protection and short circuit restorable PWM light modulator |
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| CN (1) | CN109640494B (en) |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103379698A (en) * | 2012-04-25 | 2013-10-30 | 海洋王照明科技股份有限公司 | LED constant current drive circuit with short-circuit protection |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104079276B (en) * | 2014-06-28 | 2017-01-11 | 柳州长虹机器制造公司 | High-efficiency intelligent high-side electronic load switch with wide voltage adaptability |
| CN106100307B (en) * | 2016-06-30 | 2018-12-28 | 阳光电源股份有限公司 | A kind of Switching Power Supply and its short-circuit protection method |
| CN106787774B (en) * | 2016-11-25 | 2023-06-16 | 广东百事泰医疗器械股份有限公司 | Push-pull switching circuit and soft switching three-tube push-pull forward converter |
-
2019
- 2019-01-26 CN CN201910076030.3A patent/CN109640494B/en active Active
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103379698A (en) * | 2012-04-25 | 2013-10-30 | 海洋王照明科技股份有限公司 | LED constant current drive circuit with short-circuit protection |
Non-Patent Citations (1)
| Title |
|---|
| 基于UC3842开关稳压电源的设计;黎晓贞;涂敏;;电子技术(第03期);全文 * |
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| CN109640494A (en) | 2019-04-16 |
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Address after: No. 253, Hengli Junma Road, Hengli Town, Dongguan, Guangdong 523460 Applicant after: Guangdong Qingzhou Photoelectric Technology Co.,Ltd. Address before: 523000 workshop, No.3, xiaotiantou 1st Road, Xinsi village, Hengli Town, Dongguan City, Guangdong Province Applicant before: LETARON ELECTRONIC CO.,LTD. |
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