The Si9978 is an integrated driver for an n-channel MOSFET H-bridge. The mode control allows operation as either a full H-bridge driver or as two independent half-bridges. The DIR/PWM input configuration allows easy implementation of either sign/magnitude or anti-phase PWM drive schemes for full H-bridges. Schmitt triggers on the inputs provide logic signal compatibility and hysteresis for increased noise immunity. An internal low-voltage regulator allows the device to be powered directly from a system supply of 20 to 40 volts. All n-channel gates are driven directly from low-impedance outputs. The addition of one external capacitor per half-bridge allows internal circuitry to level shift both the power supply and