Automatic dimming lamp circuit based on hysteresis comparator

Abstract

The invention discloses an automatic dimming lamp circuit based on a hysteresis comparator and relates to the field of dimming desk lamp circuits. The circuit comprises a rectifying unit, a hysteresiscomparator, a dimming unit and an LED lamp. The rectifying unit, the hysteresis comparator, the dimming unit and the LED lamp are electrically connected in sequence. The hysteresis comparator comprises an operational amplifier U2A, a voltage stabilizing tube D11, a resistor R12, a resistor R10 and a resistor R13. A non-inverting input end of the operational amplifier U2A is connected to the voltage stabilizing tube D11 and then is grounded, the non-inverting input end of the operational amplifier U2A is connected to an output end of the operational amplifier U2A via the resistor R13, a positive power supply end of the operational amplifier U2A is connected to the voltage stabilizing tube D11 via the resistor R10, the non-inverting input end of the operational amplifier U2A is connected toan output of the rectifying unit, and an output end of the operational amplifier U2A is connected to the dimming unit. According to the automatic dimming lamp circuit, the problem of poor anti-interference performance of a circuit caused by a condition that an existing dimming lamp circuit does not filter rectified jitter due to the complicated design of the circuit is solved, the stability of output level is achieved, and the effect of anti-interference performance of the circuit is improved.

Description

technical field [0001] The invention relates to the field of dimming desk lamp circuits, in particular to an automatic dimming desk lamp circuit based on a hysteresis comparator. Background technique [0002] Desk lamps are divided into touch-type desk lamps and brightness-adjustable ones; the principle of touch-type desk lamps is to install electronic touch ICs inside to form a control loop with the electrodes at the touch of the desk lamp; when the human body touches the sensing electrodes, the touch signal is transmitted by The pulse signal generated by the pulsating direct current is sent to the touch sensing terminal, and then the touch sensing terminal will send out a trigger pulse signal to control the light on; if it is touched again, the touch signal will be sent to the touch sensing terminal by means of a pulse signal generated by the pulsating direct current. When the touch sensing terminal stops sending the trigger pulse signal, when the AC power crosses zero, th...

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Problems solved by technology

[0004] The object of the present invention is: the present invention provides a hysteresis comparator-based automatic dimming desk lamp circuit, which solves the problem of circuit resistance in the existing dimming desk lamp circuit due to the complex design of the circuit that does not filter out the jitter after rectification. The problem of poor interference

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