The HT7Q1521 is a high voltage analog-front-end IC for 3 to 8 cell Li-ion rechargeable battery protection. It consists of an accumulative cell voltage monitor and a high accuracy voltage regulator. The device is designed to monitor an accumulative voltage from 1 to N and outputs the divide-by-N voltage to the analog multiplexer with a ±0.5% divided ratio accuracy. The anti-reverse current switch is implemented to prevent a backflow current even if VOUT is higher than VBATn. Each divided accumulative cell voltage can be observed sequentially from VBAT1 to VBAT8 which benefits MCUs with a lower number of ADCs. There are 3 control bits, B0, B1 and B2, to select which terminal voltage outputs with a maximum 100Hz scanning frequency when COUT=2.2nF. The enable pin, EN_S, is used to close all switches and the output voltage is pulled down by an internal 1MΩ resistor. An integrated regulator provides a 5V supply to the MCU with a 30mA driving current capability and which has ±1% accuracy. The voltage regulator and cell voltage monitor are shut down with an ultra-low standby current of 0.1μA when the device is in the Sleep Mode. When the HVWK pin is triggered by a voltage greater than its threshold, the device will return to the normal operating state.

Specification:

• cell #: 3~8
• input voltage: 7.5V~36V
• control I/F: I/O
• VMON voltage monitor type: accumulative
• VMON accuracy: 1/n±0.5% (ratio)
• LDO: 5V±1%
• HV wake up: 1CH
• case: 24SSOP