TPS2834_15 Datasheet, PDF (3/25 Pages) Texas Instruments – SYNCHRONOUS-BUCK MOSFET DRIVERS WITH DEAD-TIME CONTROL

TPS2834, TPS2835
SYNCHRONOUSĆBUCK MOSFET DRIVERS
WITH DEADĆTIME CONTROL
SLVS223B − NOVEMBER 1999 − REVISED AUGUST 2002
Terminal Functions
TERMINAL
NAME
NO.
BOOT
14
BOOTLO
11
CROWBAR
3
DT
ENABLE
HIGHDR
IN
LOWDR
NC
PGND
SYNC
VCC
6
1
12
2
10
4, 9, 13
7
5
8
I/O
DESCRIPTION
I Bootstrap terminal. A ceramic capacitor is connected between BOOT and BOOTLO to develop the floating
bootstrap voltage for the high-side MOSFET. The capacitor value is typically between 0.1 µF and 1 µF.
O This terminal connects to the junction of the high-side and low-side MOSFETs.
I CROWBAR can to be driven by an external OVP circuit to protect against a short across the high-side
MOSFET. If CROWBAR is driven low, the low-side driver will be turned on and the high-side driver will be
turned off, independent of the status of all other control terminals.
I Dead-time control terminal. Connect DT to the junction of the high-side and low-side MOSFETs.
I If ENABLE is low, both drivers are off.
O Output drive for the high-side power MOSFET
I Input signal to the MOSFET drivers (noninverting input for the TPS2834; inverting input for the TPS2835).
O Output drive for the low-side power MOSFET
No internal connection
Power ground. Connect to the FET power ground.
I Synchronous rectifier enable terminal. If SYNC is low, the low-side driver is always off; If SYNC is high, the
low-side driver provides gate drive to the low-side MOSFET.
I Input supply. Recommended that a 1-µF capacitor be connected from VCC to PGND.
detailed description
low-side driver
The low-side driver is designed to drive low r_DS(on) N-channel MOSFETs. The current rating of the driver is 2 A,
source and sink.
high-side driver
The high-side driver is designed to drive low r_DS(on) N-channel MOSFETs. The current rating of the driver is 2 A,
source and sink. The high-side driver can be configured as a GND-reference driver or as a floating bootstrap
driver. The internal bootstrap diode is a Schottky, for improved drive efficiency. The maximum voltage that can
be applied from BOOT to ground is 30 V.
dead-time (DT) control
Dead-time control prevents shoot-through current from flowing through the main power FETs during switching
transitions by controlling the turnon times of the MOSFET drivers. The high-side driver is not allowed to turn
on until the gate drive voltage to the low-side FET is low, and the low-side driver is not allowed to turn on until
the voltage at the junction of the power FETs (Vdrain) is low; the TTL-compatible DT terminal connects to the
junction of the power FETs.
ENABLE
The ENABLE terminal enables the drivers. When enable is low, the output drivers are low. ENABLE is a
TTL-compatible digital terminal.
IN
The IN terminal is a TTL-compatible digital terminal that is the input control signal for the drivers. The TPS2834
has a noninverting input; the TPS2835 has an inverting input.
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