ADP5360ACBZ-2-R7 datasheet(28/60 Pages) AD

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ADP5360

Data Sheet

Rev. 0 | Page 28 of 60

BATTERY PROTECTION

TheADP5360 features a full battery protection feature for Li-Ion

and Li-Poly batteries. By default, after VISOB rises higher than

VUVLO and exits from shipment mode, battery protection is enabled.

The ADP5360 supports the following fault protections:

•

Undervoltage protection when the battery overdischarges

•

Overdischarge current protection

•

Overvoltage protection when the battery overcharges

•

Overcharge current protection

When VBSNS is lower than the battery undervoltage threshold after

deglitch time, undervoltage protection triggers, the isolation FET

turns off and isolates all system load to the ISOB pin, and the

BAT_UV_STATUS bit is set high to indicate the battery status

and fault register assertion. During undervoltage protection, the

charger allows charge to the battery if the EN_CHGLB bit,

Address 0x11, is set to high, and the charger exits undervoltage

protection when the battery voltage becomes higher than the

undervoltage threshold. The charger does not allow any charge for

battery safety consideration if the EN_CHGLB bit is set low. Use

the I2C interface to select the undervoltage threshold and

response time.

When the battery discharge current going through the isolation

FET increases and rises higher than the overcurrent threshold

after deglitch time, the overcurrent protection is triggered, and

the isolation FET turns off and isolates all system load to the

ISOB pin. This protection behavior can be selected to latch-up

protection mode or hiccup mode by setting the OC_DIS_HICCUP

bit, Address 0x11. In latch-up protection mode, the isolation

FET turns off and shuts down the VSYS output after retrying

three times. When the fault is removed, clearing the fault

In hiccup protection mode, the isolation FET attempts to turn

on after the typical 200 ms shutdown time until the system load

fault is removed.

When triggering battery overvoltage protection, the LDO FET

turns off, charging stops, and the LDO FET stays in suspend

status. Duirng this protection, the isolation FET is selectable and

can be turned off or kept turned.

When triggering the battery overcharge current, the LDO FET

turns off, charging stops, and the LDO FET stays in suspend status.

The isolation FET also turns off and shuts down the VSYS output.

If selecting the latch-up overcharge protection mode, the charger

remains in suspend status, and the battery does not allow charging

after three retries. If selecting hiccup protection mode, the

charger always attempts to restart the charge until the charger

fault is removed. Clearing the fault register or VBUS power reset

can recover normal operation after the fault is removed.

All battery protection function selection must be done when the

ADP5360 powers up. Do not change the battery protection

function during battery fault.

BUCK REGULATOR OPERATION

Operation Mode

The ADP5360 has two operation modes, PWM and hysteresis

that are controlled by the I2C interface.

PWM Mode

In PWM mode, the buck regulator operates at a fixed 1 MHz

frequency that is set by an internal oscillator. At the start of each

oscillator cycle, the high-side MOSFET switch turns on and sends a

positive voltage across the inductor. The inductor current increases

until the current sense signal exceeds the peak inductor current

threshold, which turns off the high-side MOSFET switch. This

threshold is set by the error amplifier output. During the high-side

MOSFET off time, the inductor current decreases through the

low-side MOSFET until the next oscillator clock pulse starts a

new cycle.

In PWM mode, the regulator can supply up to 500 mA of average

output current. The regulator can provide lower voltage ripple

in PWM mode, which is useful for noise sensitive applications.

Hysteresis Mode

In hysteresis mode, the buck regulator in the ADP5360 charges

the output voltage to a higher value than the nominal output

voltage with PWM pulses. The buck regulator charges the

output voltage by regulating the constant peak inductor current

that is programed by the I2C interface. When the output sense

signal exceeds the hysteresis upper threshold, the regulator enters

standby mode. In standby mode, the high-side and low-side

MOSFETs and the control circuitry are disabled to allow a low

quiescent current as well as a high efficiency performance.

During standby mode, the output capacitor supplies energy into

the load, and the output voltage decreases until the voltage falls

lower than the hysteresis comparator lower threshold. The buck

regulator wakes up and generates the PWM pulses to charge the

output again.

Because the output voltage occasionally enters standby mode

and then recovers, the output voltage ripple in hysteresis mode

is larger than the ripple in PWM mode. The varying switching

frequency creates more noise in the system. Therefore, it is

recommended to use PWM mode during charging status.

Use the following equation in hysteresis mode to calculate the

regulator output current:

ILOAD1_HYS = IPEAK1_HYS/2

where:

ILOAD1_HYS is the regulator output current.

IPEAK1_HYS is the inductor peak current.

The maximum regulator output current is 100 mA when the

limitation of the inductor peak current, BUCK_ILIM, is set to

200 mA.

ADP5360ACBZ-2-R7 Datasheet(PDF) 28 Page - Analog Devices

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