Remote control touch dimming circuit composed of BA5204

The figure below shows a remote control touch dimming switch circuit. It can be controlled by infrared remote control or dimmed by hand touch without interfering with each other, and is very convenient to use.

In the figure, BA5204 is a decoding integrated circuit, and its ⑩ pin is connected to R4 and C1 for the timing of the internal oscillator; ③~⑩ pins are control output terminals, of which ③~⑧ pins are non-hold terminals, that is, when a key in the transmitting circuit is pressed, a corresponding terminal of BA5204 outputs a high level; when the key is lifted, the corresponding terminal will restore to a low level, and the time of maintaining the high level is consistent with the time of pressing the control key. The ⑨ and ⑩ pins of BA5204 are holding terminals, that is, they are low level when just powered on, and output high level when the corresponding control key is pressed, and will continue to maintain a high level even if the key is lifted. Only by pressing this key again will the output terminal return to a low level, so the two output terminals of pins ⑨ and ⑩ are suitable for remote control switch control.

IC1 is an infrared receiving head. After the infrared light modulation signal sent from the infrared transmitting circuit is received by IC1, it is amplified and demodulated to output the coded negative pulse string that can be recognized by BA5204, and then input to the ② pin of IC2 after being inverted by VT1. This circuit uses the ⑧ pin of IC2 as the dimming control output terminal. Its output signal is level-converted and inverted by VT2 and VT3, and then sent to the dimming circuit for dimming control.

lC3 is a special dimming integrated circuit LS7232. IC3 has 3 input control terminals. This circuit only uses the remote control function of pin 6 and the touch control function of pin 5. Pin 8 of IC3 is the thyristor trigger pulse output terminal. It outputs negative pulses with a current of 25mA, which can directly drive thyristors with a power of more than kilowatts.