UC3727

UC1727 UC2727 UC3727 Isolated High Side IGBT Driver FEATURES Receives Power and Signal from Single Isolation Transformer Generates Split Rail for 4A Peak Bipolar Gate Drive 16V High Level Gate Drive Low Level Gate Drive more Negative than -5V Undervoltage Lockout Desaturation Detection and Fault Processing Separate Output Enable Input Programmable Stepped Gate Drive for Soft Turn On Programmable Stepped Gate Drive for Soft Fault DESCRIPTION The UC1727 and its companion chip, the UC1726, provide all the necessary features to drive an isolated IGBT transistor from a TTL input signal. A unique modulation scheme is used to transmit both power and signal across an isolation boundary with a minimum of external components. Protection features include under voltage lockout and desaturation detection. High level gate drive signals are typically 16V. Intermediate high drive levels can be programmed for various periods of time to limit surge current at turn on and in the event of desaturation due to a short circuit. The chip generates a bipolar supply so that the gate can be driven to a negative voltage insuring the IGBT remains off in the presence of high common mode slew rates. Uses include isolated off-line full bridge and half bridge drives for motors, switches, and any other load requiring full electrical isolation. BLOCK DIAGRAM UDG-94005-2 12/94 ABSOLUTE MAXIMUM RATINGS Supply voltage (VCC - VEE). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ....