Imax is the maximum current of the circuit in the DC case. Located in the PWM duty cycle for the m circuit current values fluctuate around the current value at the time t1, the charging curve should meet the following criteria: the point t charge curve slope, k1, a point discharge curve is k2, should k1mT = | k2 | (1-m) T, the current drive circuit of LED gu10 downlight to maintain a tiny fluctuations in the vicinity of a constant value.
The use of computer online through RS-485 control the PWM duty cycle changes needed in the 256 stalls, each with a computer to the RS-485 sends two-byte hex commands, thus changing the C8051 produce the duty cycle to change the brightness of LED gu10 downlight.
The main function of the RS-485 interface circuit is: will send a signal from the microprocessor, TX through the “transmitter” to convert the differential signal in the communication network of led high bay light, can also communication network in the differential signal through the receiver to convert microprocessor to receive the RX signal. Any one time, one RS-485 transceiver can only work in two modes “receive” or “Send”. Therefore, the circuit shown in Figure 6, the R / D signal output by the microprocessor directly control SN75LBC184 chip transmitter / receiver enable: R / D signal to “1”, the SN75LBC184 chip transmitter. The receiver is disabled, the microprocessor can SN75LBC184. Range of high duty cycle segment, due to the charging curve slope approaching the same, the current value tends to be the maximum in the low-range segment, shorter charging time, circuit loss, the inductor current value close to zero.