WIDE-INPUT SYNCHRONOUS BUCK CONTROLLER
DESCRIPTION
The TPS40060 and TPS40061 are high-voltage, wide input (10 V
to 55 V) synchronous, step-down con verters. This family
of devices offers design flexibility with avariety of user
programmable functions, including;soft-start, UVLO, operating
frequency, voltage feed-forward, high-side current limit, and
loop com- pensation. These devices are also synchronizable
to an external supply.
The TPS40060 and TPS40061 incorporate MOSFET gate drivers for
external P-channel high-side and
N-channel synchronous rectifier (SR) MOSFETs. Gate drive logic
incorporates anti-cross conduction circuitry to prevent
simultaneous high-side and synchronous rectifier conduction.
TERMINAL NAME NO. | I/O | DESCRIPTION |
BP5 3 | O | 5-V reference. This pin should be bypassed to ground with a 0.1-µF
ceramic capacitor. This pin may be used wit an external DC
load of 1 mA or less. |
BP10 11 | O | 10-V reference used for gate drive of the N-channel synchronous
rectifier. This pin should be bypassed by a 1-µF ceramic
capacitor. This pin may be used with an external DC load of 1 mA or
less. |
BPN10 13 | O | Negative 8-V reference with respect to VIN. This voltage is used to
provide gate drive for the high side P-channel MOSFET. This
pin should be bypassed to VIN with a 0.1-µF capacitor |
COMP 8 | I | Output of the error amplifier, input to the PWM comparator. A
feedback network is connected from this pin to the VFB pin to
compensate the overall loop. The comp pin is internally clamped
above the peak of the ramp to improve large signal transient
response |
HDRV 14 | O | Floating gate drive for the high-side P-channel MOSFET. This pin
switches from VIN (MOSFET off) to BPN10 (MOSFET on). |
ILIM 16 | I | Current limit pin, used to set the overcurrent threshold. An
internal current sink from this pin to ground sets a voltage
drop across an external resistor connected from this pin to VIN.
The voltage on this pin is compared to thevoltage drop (VIN -SW)
across the high side MOSFET during conduction. |
KFF 1 | I | A resistor is connected from this pin to VIN to program the amount
of voltage feed-forward. The current fed into this pin is
internally divided and used to control the slope of the PWM ramp. |