Datasheet

TPS62410-Q1
www.ti.com SLVSAA8 –MARCH 2010
Under-Voltage Lockout
The under voltage lockout circuit prevents the device from malfunctioning at low input voltages and from
excessive discharge of the battery and disables the converters. The under-voltage lockout threshold is typically
1.5V, max 2.35V. In case the default register values are overwritten by the Interface, the new values in the
registers REG_DEF_1_Low and REG_DEF_2 remain valid as long the supply voltage does not fall under the
under-voltage lockout threshold, independent of whether the converters are disabled.
MODE SELECTION
The MODE/DATA pin allows mode selection between forced PWM Mode and Power Save Mode for both
converters. Furthermore, this pin is a multipurpose pin and provides (besides Mode selection) a one-pin interface
to receive serial data from a host to set the output voltage. This is described in the section EasyScale Interface.
Connecting this pin to GND enables the automatic PWM and power save mode operation. The converters
operate in fixed-frequency PWM mode at moderate to heavy loads and in the PFM mode during light loads,
maintaining high efficiency over a wide load current range.
Pulling the MODE/DATA pin high forces both converters to operate constantly in the PWM mode even at light
load currents. The advantage is the converters operate with a fixed frequency that allows simple filtering of the
switching frequency for noise sensitive applications. In this mode, the efficiency is lower compared to the power
save mode during light loads. For additional flexibility it is possible to switch from Power Save Mode to forced
PWM mode during operation. This allows efficient power management by adjusting the operation of the converter
to the specific system requirements.
In case the operation mode will be changed from forced PWM mode (MODE/DATA = high) to Power Save Mode
Enable (MODE/DATA = 0) the Power Save Mode will be enabled after a delay time of typically t
timeout
, which is a
maximum of 520µs.
The forced PWM Mode operation is enabled immediately with Pin MODE/DATA set to 1.
ENABLE
The device has for each converter a separate EN pin to start up each converter independently. If EN1, EN2 are
set to high, the corresponding converter starts up with soft start as previously described.
Pulling EN1 and EN2 pin low forces the device into shutdown, with a shutdown quiescent current of typically
1.2µA. In this mode, the P and N-Channel MOSFETs are turned-off and the entire internal control circuitry is
switched-off. For proper operation the EN1 and EN2 pins must be terminated and must not be left floating.
DEF_1 PIN FUNCTION
The DEF_1 pin is dedicated to converter 1 and works as an analog input for adjustable output voltage setting.
Connecting an external resistor network to this pin adjusts the default output voltage to any value starting from
0.6V to V
IN
.
180° OUT OF PHASE OPERATION
In PWM Mode the converters operate with a 180° turn-on phase shift of the PMOS (high side) transistors. It
prevents the high side switches of both converters to be turned on simultaneously, and therefore smooths the
input current. This feature reduces the surge current drawn from the supply.
SHORT-CIRCUIT PROTECTION
Both outputs are short-circuit protected with maximum output current = I
LIMF
(P-MOS and N-MOS). Once the
PMOS switch reaches its current limit, it will be turned off and the NMOS turned on. The PMOS only turns on
again, once the current in the NMOS decreases below the NMOS current limit.
THERMAL SHUTDOWN
As soon as the junction temperature, T
J
, exceeds typically 150°C the device goes into thermal shutdown. In this
mode, the P and N-Channel MOSFETs are turned-off. The device continues its operation when the junction
temperature falls below the thermal shutdown hysteresis again.
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