Datasheet

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CHARGE STATUS OUTPUTS

PG OUTPUT

CE INPUT (CHARGE ENABLE)

TTE INPUT (TIMER AND TERMINATION ENABLE)

THERMAL SHUTDOWN AND PROTECTION

TE INPUT (TIMER ENABLED)

bq24020 , , bq24022 , , bq24023

bq24024 , bq24025 , bq24026

bq24027

SLUS549E – DECEMBER 2002 – REVISED NOVEMBER 2007

The open-drain STAT1 and STAT2 outputs indicate various charger operations as shown in the following table.

These status pins can be used to drive LEDs or communicate to the host processor. Note that OFF indicates the

open-drain transistor is turned off.

Table 1. Status Pins Summary

(1)

CHARGE STATE STAT1 STAT2

Precharge in progress ON ON

Fast charge in progress ON OFF

Charge done OFF ON

Charge suspend (temperature) OFF OFF

Timer fault OFF OFF

Sleep mode OFF OFF

(1) OFF means the open-drain output transistor on the STAT1 and STAT2 pins is in an off state.

The open-drain PG (power Good) indicates when the AC adapter is present. The output turns ON when a valid

voltage is detected. This output is turned off in the sleep mode. The PG pin can be used to drive an LED or to

communicate to the host processor.

The CE digital input is used to disable or enable the charge process. A low-level signal on this pin enables the

charge. A high-level signal disables the charge, and places the device in a low-power mode. A high-to-low

transition on this pin also resets all timers and timer fault conditions. Note that this applies to both AC and USB

charging.

The TTE digital input is used to disable or enable the fast-charge timer and charge-taper detection. A low-level

signal on this pin enables the fast-charge timer and taper timer, and a high-level signal disables this feature.

Note that this applies to both AC and USB charging.

The bqTINY-II monitors the junction temperature, T

, and suspends charging if T

exceeds T

(SHTDWN).

Charging

resumes when T

falls approximately 15 ° C below T

(SHTDWN)

The TE digital input is used to disable or enable the fast-charge timer. A low-level signal on this pin enables the

fast-charge timer and a high-level signal disables this feature.

Note that this applies to both AC and USB charging.

Product Folder Link(s): bq24020 bq24022 bq24023 bq24024 bq24025 bq24026 bq24027