A high-voltage integrated circuit for power supply applications

A new high-voltage integrated circuit (HVIC) is described which controls either PWM or Resonant half-bridge circuit topologies for power supply applications at frequencies up to 1 MHz. The HVIC technology allows the two power FETs in half-bridge circuit arrangements to be driven from a single silicon chip thus eliminating external, isolated gate drivers. Isolation for the "upper" FET gate driver is achieved on-chip using the HVIC technology. Communication with the "upper" gate drive is also achieved with an on-chip high voltage transistor operated as a current source. The chip has the usual power supply control functions (including current-mode control) as well as a voltage-controlled oscillator (VCO) for resonant converter control. In addition, a novel pulse detector circuit is included to allow the chip to receive isolated pulses from a secondary side control, thus achieving simple digital isolation between primary and secondary.