ADP5350ACBZ-1-R7 datasheet(24/63 Pages) AD

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ADP5350

Data Sheet

Rev. B | Page 24 of 63

tBATOK timer expires, the charger assumes that no battery is

present. If the BSNS does not exceed the VBATH voltage when the

tBATOK timer expires, the charger assumes that a battery is present,

and begins a new charge cycle.

When the ADP5350 battery monitor is enabled and detects that

the battery voltage is higher than VWEAK, Bit 2 in Register 0x36,

BATOK, asserts high. The PGOOD pin can be programmed to

mask BATOK, which indicates whether the battery voltage is

higher than VWEAK.

Battery (ISOB) Short Detection

A battery short occurs under a damaged battery condition or

when the battery protection circuitry is enabled.

After a source phase, if the voltage on ISOB or BSNS remains

below VBATH, either the battery voltage is low or the battery node

is shorted. When the battery voltage is low, trickle charge mode is

initiated (see Figure 42). If the voltage on BSNS remains below

VBAT_SHR after tBAT_SHR has elapsed, the ADP5350 assumes that the

battery node is shorted. A fault is declared on Register 0x0A, Bit 3.

The trickle charge branch is active during the battery short

scenario, and trickle charge current to the battery is maintained

until the 60 minutes of the trickle charge mode timer expires.

BATTERY TEMPERATURE

Battery Pack Thermistor Input

The ADP5350 charger features battery pack temperature sensing

that precludes charging when the battery pack temperature is

outside the specified range. The THR pin provides an on and

off switching current source, which must be connected directly

to the battery pack thermistor, RNTC. The activation interval of

the THR current source is 167 ms.

The battery pack temperature sensing can be controlled by I2C

using the conditions shown in Table 12. Note that the I2C register

default setting for EN_THR (Register 0x07) is 0 = temperature

sensing off.

Table 12. THR Input Function

Conditions

THR Function

VBUSx

VISOB

Open or VBUS = 0 V to 4.0 V

<2.5 V

Off

Open or VBUS = 0 V to 4.0 V

>2.5 V

Controlled by I2C

VBUS = 4.0 V to 5.5 V

Don't care

Always on

If the battery pack thermistor is not connected directly to the

ADP5350 THR pin, connect a 47 kΩ (tolerance ±20%) dummy

resistor between THR and AGND. Leaving the THR pin open

results in a false detection of the battery temperature of <0°C and

charging being disabled. Alternatively, select the temperature

source from the I2C interface by setting Register 0x20, Bit 6.

The ADP5350 charger suspends charging if the battery tempera-

ture is outside the range of less than 0°C or greater than 60°C.

For temperatures greater than 0°C, and likewise for temperatures

lower than 60°C, the THR_STATUS[2:0] bits are set accordingly.

The ISOFET remains on while the dc-to-dc regulator shuts down.

The ADP5350 charger is designed for use with a negative

temperature coefficient (NTC) thermistor in the battery pack

with a nominal resistance value of 47 kΩ, 10 kΩ, or 100 kΩ at

25°C, which is selected via the I2C interface in Register 0x0C,

Bit 4, and Register 0x3D, Bit 0. The temperature coefficient

curve (beta) of RNTC also can be fuse selected in the ADP5350.

Figure 41. Battery Detection Sequence

Figure 42. Battery Short Detection Sequence

ISOB

SINK PHASE

LOGIC

STATUS

OPEN

SHORT

tBAT_OK

VBATL

ISOB

OPEN

LOGIC

STATUS

SOURCE PHASE

tBAT_OK

VBATH

SINK PHASE

SOURCE PHASE

TRICKLE CHARGE

ISOB

LOGIC

STATUS

OPEN

SHORT

tBAT_OK

LOGIC

STATUS

SHORT

LOW

BATTERY

tBAT_OK

LOGIC

STATUS

SHORT

tBAT_SHR

VBATL

VBATH

VBAT_SHR

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