FEATURES
H-Bridge or Dual Half-Bridge Operation
20- to 40-V Supply
Static (dc) Operation
Cross-Conduction Protected
Current Limit
Undervoltage Lockout
ESD Protected
Fault Output
DESCRIPTION
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
logic signal for the high-side n-channel gate drives. Internal
charge pumps replace leakage current lost in the high-side
driver circuits to provide “static” (dc) operation in any output
condition. Protection features include an undervoltage
lockout, cross-conduction prevention logic, and overcurrent
monitors.
The Si9978 is available in both standard and lead (Pb)-free,
24-pin wide-body SOIC (surface mount) packages, specified
to operate over the industrial (−40 to +85 ℃) temperature
range.