BQ24070RHLRG4 Datasheet, PDF (19/31 Pages) Texas Instruments – SINGLE-CHIP LI-ION CHARGE AND SYSTEM POWER-PATH MANAGEMENT IC

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bq24070
bq24071
SLUS694F – MARCH 2006 – REVISED DECEMBER 2009
The bq24070/1 enters the low-power standby mode if while input power is present, the CE input is low. In this
suspend mode, internal power FET Q1 (see Figure 5) is turned off, the BAT input is used to power the system
through the OUT pin. This feature is designed to limit the power drawn from the input supply (such as USB
suspend mode).
Charge Status Outputs
The open-drain (OD) STAT1 and STAT2 outputs indicate various charger operations as shown in Table 2. 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. Note that this assumes CE = High.
Table 2. Status Pins Summary
CHARGE STATE
Precharge in progress
Fast charge in progress
Charge done
Charge suspend (temperature), timer fault, and sleep mode
STAT1
ON
ON
OFF
OFF
STAT2
ON
OFF
ON
OFF
PG, Outputs (Power Good)
The open-drain pin, PG, indicates when input power is present, and above the battery voltage. The
corresponding output turns ON (low) when exiting sleep mode (input voltage above battery voltage). This output
is turned off in the sleep mode (open drain). The PG pin can be used to drive an LED or communicate to the
host processor. Note that OFF indicates the open-drain transistor is turned off.
CE Input (Chip Enable)
The CE (chip enable) digital input is used to disable or enable the IC. A high-level signal on this pin enables the
chip, and a low-level signal disables the device and initiates the standby mode. The bq24070/1 enters the
low-power standby mode when the CE input is low with input present. In this suspend mode, internal power FET
Q1 (see block diagram) is turned off; the battery (BAT pin) is used to power the system via Q2 and the OUT pin.
This feature is designed to limit the power drawn from the input supply (such as USB suspend mode).
Charge Disable Functions
The DPPM input can be used to disable the charge process. This can be accomplished by floating the DPPM
pin.
Timer Fault Recovery
As shown in Figure 4, bq24070/1 provides a recovery method to deal with timer fault conditions. The following
summarizes this method:
Condition 1: Charge voltage above recharge threshold (V_(RCH)) and timeout fault occurs.
Recovery Method: bq24070/1 waits for the battery voltage to fall below the recharge threshold. This could
happen as a result of a load on the battery, self-discharge, or battery removal. Once the battery falls below the
recharge threshold, the bq24070/1 clears the fault and starts a new charge cycle. A POR or CE toggle also
clears the fault.
Condition 2: Charge voltage below recharge threshold (V_(RCH)) and timeout fault occurs.
Recovery Method: Under this scenario, the bq24070/1 applies the I_(FAULT) current. This small current is used to
detect a battery removal condition and remains on as long as the battery voltage stays below the recharge
threshold. If the battery voltage goes above the recharge threshold, then the bq24070/1 disables the I_(FAULT)
current and executes the recovery method described for condition 1. Once the battery falls below the recharge
threshold, the bq24070/1 clears the fault and starts a new charge cycle. A POR or CE toggle also clears the
fault.
Copyright © 2006–2009, Texas Instruments Incorporated
Product Folder Link(s): bq24070 bq24071
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