BQ24165_14 Datasheet, PDF (18/38 Pages) Texas Instruments – 2.5A, Dual-Input, Single Cell Switch Mode Li-Ion Battery Charger with Power Path Management

bq24165
bq24166
bq24167
SLUSAP4B – DECEMBER 2011 – REVISED MARCH 2013
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Where I_{IN_LIM} is the programmed input current limit and K_ILIM is the programming factor found in the Electrical
Characteristics table.
The bq24165/6/7 manages the dual input supply paths as well. The IN input has precedence when valid supplies
are connected to both inputs. The two inputs are always isolated from one another. The bq24165/6/7 always
seeks to charge from a valid source. For example, if a valid source is connected to USB and a source is
connected to IN that is greater than the OVP threshold, the USB source is used to charge the battery. In this
case, both the USB source and the battery would be isolated from the OVP source connected to the IN input.
BATTERY ONLY CONNECTED
When the battery is connected with no input source, the internal battery FET is turned on similar to supplement
mode. In this mode, the current is not regulated; however, there is a short circuit current limit. If the short circuit
limit is reached, the battery FET is turned off for the deglitch time. After the deglitch time, the battery FET is
turned on in order to determine if the short has been removed. If not, the FET turns off and the process repeats
until the short is removed.
EXTERNAL BATTERY DISCHARGE FET (BGATE)
The bq24165/6/7 contains a MOSFET driver to drive an external P-Channel MOSFET between the battery and
the system output. This external FET provides a low impedance path to supply the system from the battery.
Connect BGATE to the gate of the external discharge MOSFET. BGATE is on under the following conditions:
1. No valid input supply connected.
2. IUSB1=IUSB2=IUSB3=high (High Impedance Mode)
This FET is optional and runs in parallel with the internal charge FET during discharge. Note that this FET is not
protected by the short circuit current limit.
SAFETY TIMER
At the beginning of charging process, the bq24165/6/7 starts the 6 hour safety timer. This timer is active during
the entire charging process. If charging has not terminated before the safety timer expires, the charge cycle is
terminated and the battery FET is turned off. To clear the safety timer fault, charging must be resumed by using
CE1 and CE2 (bq24165) or CE(bq24166/7) or High Impedance mode or a new charge cycle started by V_SUPPLY
POR or battery remove and replace.
During the fast charge (CC) phase, several events increase the timer duration by 2X.
1. The system load current reduces the available charging current.
2. The input current needed for the fast charge current is limited by the input current loop.
3. The input current is reduced because the V_INDPM loop is preventing the supply from crashing.
4. The device has entered thermal regulation because the IC junction temperature has exceeded T_J(REG).
5. The CEx bits are reducing I_CHARGE or VBAT.
6. The battery voltage is less than V_BATSHORT.
7. The battery has entered the JEITA WARM or COLD state via the TS pin (bq24166/6) or CE1/CE2
(bq24165)configuration.
During these events, the timer is slowed by half to extend the timer and prevent any false timer faults. Starting a
new charge cycle by VSUPPLY POR or removing/replacing the battery or resuming a charge by toggling the
CE1/CE2(bq24165) or CE(bq24166/7) pins, resets the safety timer. Additionally, thermal shutdown events cause
the safety timer to reset.
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