FEATURES
• Dual High Current Drivers.
• Full Compatibility with TI Fusion Digital Power
Supply Controllers, such as UCD91xx and
UCD92xx Families
• Operational to 2 MHz Switching Frequency
• High-Side FET and Output Current Limit
Protection with Independently Adjustable
Thresholds
• Fast High-Side Overcurrent Sense Circuit with
Fault Flag Output – Prevents Catastrophic
Current Levels on a Cycle-by-Cycle Basis
• Differential High-Gain Current Sense Amplifier
• Voltage Proportional to Load Current Monitor
Output
• Wide Input Voltage Range: 4.7 V to 15 V
Operation to 2.2 V Input Supported with an
External 4.5-6.5 V Bias Supply
• Onboard Regulated Supplies for Gate Drive
and Internal Circuits
• Integrated Thermal Shutdown
• Selectable Operation Modes:
– PWM plus Synchronous Rectifier Enable
(SRE) with Automatic Dead-Time Control
– Direct High-Gate and Low-Gate Inputs for
Direct FET Control
• 3-State PWM Input for Power Stage Shutdown
• UVLO Housekeeping Circuit
• Rated from –40°C to +125°C Junction
Temperature

APPLICATIONS
• Digitally-Controlled Synchronous-Buck Power
Stages for Single- and Multi-Phase
Applications
• Digitally-Controlled Power Modules

DESCRIPTION
The UCD7232 high current driver is specifically designed for digitally-controlled, point-of-load,
synchronous buck switching power supplies. Two
driver circuits provide high charge and discharge
current for the high-side NMOS switch and the
low-side NMOS synchronous rectifier in a
synchronous buck circuit. The MOSFET gates are
driven by an internally regulated VGG supply. The
internal VGG regulator can be disabled to permit the
user to supply their own gate drive voltage. This
flexibility allows a wide power conversion input
voltage range of 2.2 to 15 V. Internal under voltage
lockout (UVLO) logic insures VGG is good before
allowing chip operation.
A drive logic block allows operation in one of two
modes selected by the SRE Mode pin. In
Synchronous Mode, the logic block uses the PWM
signal to control both the high-side and low-side gate
drive signals. Dead time is automatically adjusted to
prevent cross conduction. The Synchronous Rectifier
Enable (SRE) pin controls whether or not the low-side
FET is turned on when the PWM signal is low. In
Independent Mode, the PWM and SRE pins control
the high-side and low-side gates directly. No
anti-cross-conduction logic is used in this mode.
On-board comparators monitor the voltage across the
high side switch and the voltage across an external
current sense element to safeguard the power stage
from sudden high current loads. Blanking delay is set
for the high side comparator by a single resistor in
order to avoid false reports coincident with switching
edge noise. In the event of a high-side fault or an
over-current fault, the high-side FET turned off and
the Fault Flag (FLT) is asserted to alert the digital
controller. The fault thresholds are independently set
by the HS Sense and ILIM pins.
Output current is measured and monitored by a
precision, high gain, switched capacitor differential
amplifier that processes the voltage present across
an external current sense element. The amplified
signal is available for use by the digital controller on
the IMON pin. The current sense amplifier has output
offset of 0.5 V so that both positive (sourcing) and
negative (sinking) current can be sensed.