CN204886902U - Pulse width modulator - Google Patents
Pulse width modulator Download PDFInfo
- Publication number
- CN204886902U CN204886902U CN201520686367.3U CN201520686367U CN204886902U CN 204886902 U CN204886902 U CN 204886902U CN 201520686367 U CN201520686367 U CN 201520686367U CN 204886902 U CN204886902 U CN 204886902U
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- China
- Prior art keywords
- operational amplifier
- resistance
- pin
- pulse width
- width modulator
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Abstract
The utility model discloses a pulse width modulator, including operational amplifier IC, operational amplifier IC's the positive pin of power connects the positive supply end, operational amplifier IC's power burden pin negative supply end, operational amplifier IC's normal phase inserts the foot through resistance R3 ground connection, operational amplifier IC's opposition inserts the foot through resistance R1 access signal input, pulse width modulator output terminal is drawn forth to operational amplifier IC's output pin, operational amplifier IC's output pin still connects to ground through resistance R5 and clamp circuit, and resistance R5 and clamp circuit's node and operational amplifier IC's opposition insert and insert resistance R2 between the foot, resistance R5 and clamp circuit's node and operational amplifier IC's normal phase insert and insert resistance R4 between the foot, electric capacity C1 connects and inserts between foot and the ground in operational amplifier IC's opposition. The utility model discloses pulse width modulator have simple, inexpensive, high -efficient, etc. The advantage.
Description
Technical field
The utility model relates to pulse modulated circuit, particularly a kind of pulse width modulator.
Background technology
The feature of pulse width modulator is that after modulation, the frequency of front and back pulse is constant, and circuit only changes the duty ratio that namely pulse duration changes pulse.This requires that pulse-width modulation scope is the half of pulse period, and voltage and pulsewidth keep synchronous.The circuit structure of existing pulse width modulator is rather complicated, and element is more, thereby increases cost.
Utility model content
In view of this, the purpose of this utility model is the pulse width modulator that a kind of structure is simple, price is lower.
For solving the problems of the technologies described above, the utility model provides a kind of pulse width modulator, comprise operational amplifier IC, the positive pin of power supply of operational amplifier IC connects positive power source terminal, the power-pin negative power end of operational amplifier IC, the positive access pin of operational amplifier IC is through resistance R3 ground connection, the anti-phase access pin of operational amplifier IC accesses signal input part through resistance R1, the output pin of operational amplifier IC draws pulse width modulator lead-out terminal, the output pin of operational amplifier IC is also connected to ground through resistance R5 and clamp circuit, and access resistance R2 between the node of resistance R5 and clamp circuit and the anti-phase access pin of operational amplifier IC, the node of resistance R5 and clamp circuit and the positive of operational amplifier IC access between pin and access resistance R4, electric capacity C1 is connected between the anti-phase access pin of operational amplifier IC and ground.
More preferably, clamp circuit comprises zener diode D1, the zener diode D2 of differential concatenation, wherein the negative electrode connecting resistance R5 of zener diode D1, and the anode of zener diode D1 connects the anode of zener diode D2, the minus earth of zener diode D2.
More preferably, operational amplifier IC is LM101A.
Compared with prior art, adopt less element to realize pulse width modulation in pulse width modulator of the present utility model: operational amplifier IC, resistance R2, resistance R3, resistance R4 and electric capacity C1 form astable multivibrator, the integrator comprising resistance R2 and C1 forms negative feedback loop, and resistance R3 and R4 forms regenerative circuit.Because amount of positive feedback is less, the voltage that the discharge and recharge of timing capacitor C1 is set up is very little.By by DC voltage or the inverting input being input to operational amplifier than the modulation signal on frequency of oscillation ground by resistance R1, pulse width modulation can be realized.This pulse width modulator has simple, inexpensive, efficient advantage, has good market prospects.
Accompanying drawing explanation
Fig. 1 is the circuit diagram of the utility model pulse width modulator.
Embodiment
In order to make those skilled in the art understand the technical solution of the utility model better, below in conjunction with the drawings and specific embodiments, the utility model is described in further detail.
See Fig. 1, it is the circuit diagram of the utility model pulse width modulator.This pulse width modulator comprises the zener diode D1 of operational amplifier IC and clamper, D2 and some resistance and electric capacity, concrete circuit structure is: 7 pin (the positive pin of power supply) of operational amplifier IC (type selecting is LM101A) meet positive power source terminal V+, 4 pin (power-pin) of operational amplifier IC meet negative power end V-, 3 pin (positive access pin) of operational amplifier IC are through resistance R3 ground connection, 2 pin (anti-phase access pin) of operational amplifier IC access signal input part Vin (± 5V) through resistance R1, 6 pin (output pin) of operational amplifier IC draw pulse width modulator lead-out terminal Vo, 6 pin of operational amplifier IC are also connected to ground through resistance R5 and clamp circuit, and access resistance R3 between the node of resistance R5 and clamp circuit and 2 pin of operational amplifier IC, resistance R4 is accessed between the node of resistance R5 and clamp circuit and 3 pin of operational amplifier IC, electric capacity C1 is connected between 2 pin of operational amplifier IC and ground.Herein, clamp circuit specifically comprises zener diode D1, the zener diode D2 of differential concatenation, wherein zener diode D1 negative electrode connecting resistance R5, and the anode of zener diode D1 connects the anode of zener diode D2, the minus earth of zener diode D2.
Effectively can realize pulse-width modulation in the present embodiment: when input voltage is 0, electric capacity C1 charge and discharge electric current (flowing through the electric current of resistance R2) is equal, and duty ratio is 50%; When input voltage is timing, electric capacity C1 charging current is the electric current sum flowing through resistance R1 and R2, and electric capacity C1 discharging current is the difference between currents flowing through resistance R1 and R2, so just changes duty ratio; When input voltage is for time negative, electric capacity C1 charging current is the difference between currents flowing through resistance R1 and R2, and electric capacity C1 discharging current is the electric current sum flowing through resistance R1 and R2.As can be seen here, the circuit duty ratio of the present embodiment and input voltage are directly proportional.
Especially, in order to improve precision and the stability of pulse modulator, operational amplifier IC is through the clamp circuit clamper by zener diode D1, zener diode D2.In this pulse-width modulation circuit, when the electric current flowing through resistance R1 is more than or equal to the electric current flowing through resistance R2, circuit will stop oscillation.So when resistance R1 is equal with resistance R2, input voltage can not exceed the burning voltage (6.2V) of zener diode D1, zener diode D2.
In the present embodiment, 2 pin of operational amplifier connect output end of stabilized voltage supply; 3 pin meet 12V voltage-stabiliser tube D5, using the burning voltage of voltage-stabiliser tube as benchmark; 6 pin connect the base stage of combination switch pipe.As output voltage 2mA lower than reference voltage, compared by 2,3 pin drawing together operational amplifier IC, its 6 pin is made to export high level, control NPN triode T1, T2 conducting, with big current to load and filter capacitor electric energy supplement, make it rise to 12V very soon, until when 2 of operational amplifier IC, 3 pin current potentials are equal, 6 pin export ground level and close NPN triode T1, T2.Along with the time increases, output voltage can decline gradually, then circuit repeats said process again.Go round and begin again, switching tube continues on off state, and makes output voltage stabilization at 12V.
Although the utility model with preferred embodiment openly as above; but it is not for limiting the utility model; any those skilled in the art are not departing from spirit and scope of the present utility model; can make possible variation and amendment, the scope that therefore protection range of the present utility model should define with the utility model claim is as the criterion.
Claims (3)
1. a pulse width modulator, it is characterized in that, comprise operational amplifier IC, the positive pin of power supply of operational amplifier IC connects positive power source terminal, the power-pin negative power end of operational amplifier IC, the positive access pin of operational amplifier IC is through resistance R3 ground connection, the anti-phase access pin of operational amplifier IC accesses signal input part through resistance R1, the output pin of operational amplifier IC draws pulse width modulator lead-out terminal, the output pin of operational amplifier IC is also connected to ground through resistance R5 and clamp circuit, and access resistance R2 between the node of resistance R5 and clamp circuit and the anti-phase access pin of operational amplifier IC, the node of resistance R5 and clamp circuit and the positive of operational amplifier IC access between pin and access resistance R4, electric capacity C1 is connected between the anti-phase access pin of operational amplifier IC and ground.
2. pulse width modulator as claimed in claim 1, it is characterized in that, clamp circuit comprises zener diode D1, the zener diode D2 of differential concatenation, the wherein negative electrode connecting resistance R5 of zener diode D1, the anode of zener diode D1 connects the anode of zener diode D2, the minus earth of zener diode D2.
3. pulse width modulator as claimed in claim 2, it is characterized in that, operational amplifier IC is LM101A.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520686367.3U CN204886902U (en) | 2015-09-07 | 2015-09-07 | Pulse width modulator |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520686367.3U CN204886902U (en) | 2015-09-07 | 2015-09-07 | Pulse width modulator |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN204886902U true CN204886902U (en) | 2015-12-16 |
Family
ID=54831222
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201520686367.3U Expired - Fee Related CN204886902U (en) | 2015-09-07 | 2015-09-07 | Pulse width modulator |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN204886902U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105490333A (en) * | 2015-12-18 | 2016-04-13 | 深圳市芯沃微电子有限公司 | Rapid charging control circuit for battery, adapter and mobile equipment |
-
2015
- 2015-09-07 CN CN201520686367.3U patent/CN204886902U/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105490333A (en) * | 2015-12-18 | 2016-04-13 | 深圳市芯沃微电子有限公司 | Rapid charging control circuit for battery, adapter and mobile equipment |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20151216 Termination date: 20160907 |