TPS40090-Q1 Datasheet, PDF (5/24 Pages) Texas Instruments – HIGH-FREQUENCY MULTIPHASE CONTROLLER

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TERMINAL
NAME
NO.
BP5
22
COMP
9
CS1
1
CS2
2
CS3
3
CS4
4
CSCN
5
DIFFO
11
DROOP
7
EN/SYNC
24
FB
10
GND
17
GNDS
13
ILIM
6
PGOOD
14
PWM1
21
PWM2
20
PWM3
19
PWM4
18
REF
8
RT
16
VIN
23
VOUT
12
SS
15
TPS40090-Q1
Terminal Functions
SLUS845C – JUNE 2008 – REVISED MAY 2011
I/O
DESCRIPTION
O
Output of an internal 5-V regulator. A 4.7-μF capacitor should be connected from this pin to ground.
For 5-V applications, this pin should be connected to VDD.
O Output of the error amplifier. The voltage at this pin determines the duty cycle for the PWM.
I
I ^{Used to sense the inductor current in the phases. Inductor current can be sensed with an external}
current sense resistor or by using an external circuit and the inductor's DC resistance. They are also
I _{used for overcurrent protection and forced current sharing between the phases.}
I
I Common point of current sense resistors or filter inductors
O
Output of the differential amplifier. The voltage at this pin represents the true output voltage without
drops that result from high current in the PCB traces
I
Used to program droop function. A resistor between this pin and the REF pin sets the desired droop
value.
A logic high signal on this input enables the controller operation. A pulsing signal to this pin
I
synchronizes the main oscillator to the rising edge of an external clock source. These pulses must be
of higher frequency than the free running frequency of the main oscillator set by the resistor from the
RT pin.
I
Inverting input of the error amplifier. In closed loop operation, the voltage at this pin is the internal
reference level of 700 mV. This pin is also used for the PGOOD and OVP comparators.
Ground connection to the device.
I Inverting input of the differential amplifier. This pin should be connected to ground at the point of load.
Used to set the cycle-by-cycle current limit threshold. If ILIM threshold is reached, the PWM cycle is
terminated and the converter delivers limited current to the output. Under these conditions the
I undervoltage threshold is reached eventually and the controller enters the hiccup mode. The controller
stays in hiccup mode for seven consecutive cycles. At the eighth cycle the controller attempts a full
start-up sequence.
O
Power good indicator of the output voltage. This open-drain output connects to the supply via an
external resistor.
O
Phase shifted PWM outputs which control the external drivers. The high output signal commands a
O _{PWM cycle. The low output signal commands controlled conduction of the synchronous rectifiers.}
O ^{These pins are also used to program various operating modes as follows: for three-phase mode,}
PWM4 is connected to 5 V; for two-phase mode, PWM2 and PWM4 are connected to 5 V.
O
O Output of an internal 0.7-V reference voltage.
I Connecting a resistor from this pin to ground sets the oscillator frequency.
I Power input for the chip. Decoupling of this pin is required.
I
Noninverting input of the differential amplifier. This pin should be connected to VOUT at the point of
load.
I Provides user programmable soft-start by means of a capacitor connected to the pin.
Copyright © 2008–2011, Texas Instruments Incorporated
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