V

OV

V

OUT (V)

t

DELAY

1

2

3

4

8

7

6

5

VDD

V5

V4

V3

OUT

VSS

V1

V2

bq771800, bq771801, bq771802

bq771803, bq771807, bq771808

bq771809, bq771815

SLUSAX1D – DECEMBER 2012 – REVISED NOVEMBER 2014

www.ti.com

6 Pin Configuration and Functions

Pin Functions

bq7718xy

Pin Name

Type I/O

Description

1

VDD

P

Power supply

2

V5

I

Sense input for positive voltage of the fifth cell from the bottom of the stack

3

V4

I

Sense input for positive voltage of the fourth cell from the bottom of the stack

4

V3

I

Sense input for positive voltage of the third cell from the bottom of the stack

5

V2

I

Sense input for positive voltage of the second cell from the bottom of the stack

6

V1

I

Sense input for positive voltage of the lowest cell in the stack

7

VSS

P

Electrically connected to IC ground and negative terminal of the lowest cell in the stack

8

OUT

O

Output drive for overvoltage fault signal

6.1 Pin Details

In the bq7718xy device, each cell is monitored independently. Overvoltage is detected by comparing the actual

circuit is activated. When the timer expires, the OUT pin goes from inactive to active state.

For NCH Open Drain Active Low configurations, the OUT pin pulls down to VSS when active (OV present) and is

high impedance when inactive (no OV).

Figure 1. Timing for Overvoltage Sensing

6.1.1 Sense Positive Input for Vx

This is an input to sense each single battery cell voltage. A series resistor and a capacitor across the cell for

each input is required for noise filtering and stable voltage monitoring.

4

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Product Folder Links: bq771800 bq771801 bq771802 bq771803 bq771807 bq771808 bq771809 bq771815