Datasheet

bq500410A

SLUSB96 – NOVEMBER 2012

www.ti.com

Over-Current Protection

The bq500410A has an integrated current protection feature which monitors the input current reported by the

current sense resistor and amplifier. If the input current exceeds a safety threshold, a fault is indicated and power

transfer is halted for one minute.

If this feature is desired, the sense resistor and amplifier are required. If this feature is not desired, the I_SENSE

input pin to the bq500410A (pin 42) should be grounded.

NOTE

Always terminate the I_SENSE pin (pin 42), either with the output of a current monitor

circuit or by connecting to ground.

MSP430G2101 Low Power Supervisor

This is an optional low-power feature. By adding the MSP430G2101, as recommended in the bq500410A

application schematic, the bq500410A device is periodically shut down to conserve power, yet all relevant states

are recalled and all running LED status indicators remain active.

Since the bq500410A needs an external low-power mode to significantly reduce power consumption, the most

direct way to reduce power is to remove its supply and completely shut it down. In doing so, however, the

bq500410A goes through a reset and any data in memory would be lost. Important information regarding charge

state, fault condition, operating mode and indicator pins driven would be cleared.

The MSP430G2101, in its role as a low-power supervisor, is used to provide accurate 'ping' timing, retains

charge state, operating mode, fault condition and all relevant operation states. The LEDs are now driven and

controlled by the MSP430, not the bq500410A, which directly drives and maintains the LED status indication

during the bq500410A reset periods. Since the LED indicators are now driven by the MSP430G2101, care

should be taken not to exceed the pin output current drive limit.

Using the suggested circuitry, a standby power reduction from 300 mW to less than 90 mW can be expected

making it possible to achieve Energy Star rating.

The user does not need to program the MSP430G2101, an off-the-shelf part can be used. The required

MSP430G2101 firmware is embedded in the bq500410A and is boot loaded at first power up, similar to a field

update. The MSP430G2101 code cannot be modified by the user.

NOTE

The user cannot program the MSP430G2101 in this system.

All Unused Pins

All unused pins can be left open unless otherwise indicated. Please refer to Table 1. Grounding of unused pins, if

it is an option, can improve PCB layout.

Product Folder Links: bq500410A