HCPL-316J characteristics of the inverter
HCPL-316J is an IGBT gate drive optocoupler manufactured by Agilent. It integrates the collector emitter voltage undersaturation detection circuit and fault state feedback circuit to ensure the reliable operation of the drive circuit. Its characteristics are: compatible with CMOS / TYL level; optical isolation, fault state feedback; switching time up to 500ns; "soft" IGBT shutdown; undersaturation detection and undervoltage lockout protection; overcurrent protection; wide operating voltage range ( 15~30V); user can configure automatic reset, auto-shutdown. DSP and the coupler combine to realize IGBT drive, making IGBT VCE under-saturation detection compact, low-cost and easy to implement, while meeting a wide range of safety and regulation needs.
Implementation of HCPL-316J protection function
HCPL-316J has built-in rich IGBT detection and protection functions, making the drive circuit more convenient, safe and reliable. The following describes the working principle of undervoltage lockout protection (UVLO) and overcurrent protection:
(1) IGBT undervoltage lockout protection (UVLO) function
During the power-on process, the chip supply voltage gradually rises from 0V to the maximum value. If the chip has an output that causes the IGBT gate voltage to be too low, it will operate in the linear amplification region. The undervoltage lockout protection (UVLO) of the HCPL316J chip solves this problem. When the voltage between VCC and VE is less than 12V, the low level is output to prevent the IGBT from operating in the linear working area and causing excessive heat and burning. The schematic is shown in Figure 1 with the UVLO section.
(2) IGBT overcurrent protection function
The HCPL-316J has an overcurrent protection function for the IGBT, which performs protection by detecting the on-voltage drop of the IGBT. As can be seen from the figure, there is a fixed 7V level inside. When the detection circuit is working, it will detect the voltage drop across the C-E pole of the IGBT compared with the built-in 7V level. When it exceeds 7V. The HCPL-316J chip outputs a low level to turn off the IGBT. At the same time, an error detection signal is fed back to the input side through the on-chip optocoupler, so as to take corresponding solutions. When the IGBT is turned off, the voltage across the C to E poles must exceed 7V, but at this time, the overcurrent detection circuit fails, and the HCPL-316J chip does not report the fault signal. In fact, due to the tube voltage drop of the diode, the chip takes a protective action when the voltage between the C and E poles of the IGBT is less than 7V.