Internal circuit and pin functions of LC219/220

LC219 is a versatile remote control coding circuit. It is not only used for infrared remote control, but also for ultrasonic and radio remote control circuits. It can also be used for dual-wire connection wired remote control circuits, as shown in Figure (a). When used for radio remote control, since the radio remote control circuit is specially equipped with a local carrier frequency oscillation circuit, the ⑩ pin can be grounded at this time to stop the internal carrier frequency oscillation circuit. LC220 is a decoding circuit used in conjunction with LC219. It includes a buffer circuit, a decoder, an output circuit and a timer, as shown in Figure (b).