BQ24616 Datasheet, PDF (21/34 Pages) Texas Instruments – JEITA Guideline Compatible Stand-Alone Synchronous Switch-Mode Li-Ion or Li-Polymer Battery Charger with System Power Selector and Low Iq

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VREF
bq24616
TS
bq24616
SLUSA49A – APRIL 2010 – REVISED MAY 2010
RT1
RT2
RTH
103AT
Figure 17. TS Resistor Network
For example, 103AT NTC thermistors are used to monitor the battery pack temperature. Select T1 = 0ºC for
COLD and T5 = 60ºC for HOT, then we get R_T2 = 6.8kΩ and R_T1 = 2.2kΩ as in the design tool SLUS175. A small
RC filter is suggested to use for system-level ESD protection.
Timer Fault Recovery
The bq24616 provides a recovery method to deal with timer fault conditions. The following summarizes this
method:
Condition 1: The battery voltage is above the recharge threshold and a timeout fault occurs.
Recovery Method: The timer fault will clear when the battery voltage falls below the recharge threshold, and
battery detection will begin. Taking CE low or a POR condition will also clear the fault.
Condition 2: The battery voltage is below the recharge threshold and a timeout fault occurs.
Recovery Method: Under this scenario, the bq24616 applies the I_FAULT current to the battery. 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, the bq24616 disables the fault
current and executes the recovery method described in Condition 1. Taking CE low or a POR condition will also
clear the fault.
PG Output
The open drain PG(power good) output indicates whether the VCC voltage is valid or not. The open drain FET
turns on whenever bq24616 has a valid VCC input (not in UVLO or ACOV or SLEEP mode). The PG pin can be
used to drive an LED or communicate to the host processor.
CE (Charge Enable)
The CE digital input is used to disable or enable the charge process. A high-level signal on this pin enables
charge, provided all the other conditions for charge are met (see Enabling and Disabling Charge). A high to low
transition on this pin also resets all timers and fault conditions. There is an internal 1MΩ pulldown resistor on the
CE pin, so if CE is floated the charge will not turn on.
Inductor, Capacitor, and Sense Resistor Selection Guidelines
The bq24616 provides internal loop compensation. With this scheme, best stability occurs when the LC resonant
frequency, f_o, is approximately 12kHz–17kHz for bq24616.
The following table provides a summary of typical LC components for various charge currents:
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