HM5465AV datasheet(4/12 Pages) HMSEMI

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◼ FUNCTIONAL DESCRIPTION

The HM5465A the voltage and current of a battery and protects it from being damaged due to overcharge voltage,

overdischarge voltage, overdischarge current, and short circuit conditions by disconnecting the battery from the load or

charger. These functions are required in order to operate the battery cell within specified limits. The device requires

only one external capacitor. The MOSFET is integrated and its RSS(ON) is as low as 60mΩ typical

Normal operating mode

If no exception condition is detected, charging and discharging can be carried out freely. This condition is called

the normal operating mode.

Overcharge Condition

When the battery voltage becomes higher than the overcharge detection voltage (VCU) during charging under

normal condition and the state continues for the overcharge detection delay time (tCU) or longer, the HM5465A turns the

charging control FET off to stop charging. This condition is called the overcharge condition. The overcharge condition is

released in the following two cases:

1. When the battery voltage drops below the overcharge release voltage (VCL), the HM5465A turns the charging

control FET on and returns to the normal condition.

2. When a load is connected and discharging starts, the HM5465A turns the charging control FET on and returns

to the normal condition. The release mechanism is as follows: the discharging current flows through an

internal parasitic diode of the charging FET immediately after a load is connected and discharging starts, and

the VM pin voltage increases about 0.7V(forward voltage of the diode) from the GND pin voltage momentarily

the HM5465A detects this voltage and releases the overcharge condition. Consequently, in the case that the

battery voltage is equal to or lower than the overcharge detection voltage (VCU), the HM5465A returns to the

normal condition immediately, but in the case the battery voltage is higher than the overcharge detection

voltage (VCU), the chip does not return to the normal condition until the battery voltage drops below the

overcharge detection voltage (VCU) even if the load is connected. In addition. If the VM pin voltage is equal to

or lower than the overcurrent 1 detection voltage when a load is connected and discharging starts, load is

connected and discharging starts, the chip does not return to the normal condition

Remark If the battery is charged to a voltage higher than the overcharge detection voltage (VCU) and the

battery voltage does not drop below the overcharge detection voltage (VCU) even when a heavy load, which

causes an overcurrent, is connected, the overcurrent 1 and overcurrent 2 do not work until the battery voltage

drops below the overcharge detection voltage (VCU). Since an actual battery has, however, an internal

impedance of several dozens of mΩ, and the battery voltage drops immediately after a heavy load which causes

an overcurrent is connected, the overcurrent 1 and overcurrent 2 work. Detection of load short-circuiting works

regardless of the battery voltage.

Overdischarge Condition

When the battery voltage drops below the overdischarge detection voltage (VDL) during discharging under

normal condition and it continues for the overdischarge detection delay time (tDL) or longer, the HM5465A turns

the discharging condition. After the discharging control FET is turned off, the VM pin is pulled up by the RVMD

resistor between VM and VDD in HM5465A. meanwhile when VM is bigger than 1.5V (typ.) (the load

short-circuiting detection voltage), the current of the chip reduced to the power-down current (IPDN). This

condition is called power-down condition. The VM and VDD pins are shorted by the RVMD resistor in the IC

HM5465A

HM5465AV Datasheet(PDF) 4 Page - Shenzhen Huazhimei Semiconductor Co., Ltd