The Shunt Regulator (Z1) on the V

regulation. These are specified below. When there is excessive current flowing into the V

then current can flow through D1 into the cell pin. When the cell pin voltage exceeds V

I

Ω when both

redundant circuits are operating.

V

Parameter

Description

Min

Typ

Max

Units

I

DETECTMIN1

Min V

100

µA

I

UNDETECTMAX

Maximum current into the V

detected.

3µA

I

DETECTMIN2

Once a charger is detected, it will remain detected unless the

current into the V

25

µA

I

CELL_SHUNT

V

With V

20

75

mA

I

DETECTMAX

Max V

15

mA

V

DETECTMAX1

Normal V

I

DETECTMAX

V

CELL

–5 mV

V

CELL

V

V

DETECTMAX2

Secondary V

V

V

11.2.2 Debounce Function

The charger debounce detects a temporary disconnect/connect of the charging power supply. This can occur when the end-user

inserts the power supply to the phone and the connection is not made cleanly, or if the connection is disturbed (such as dropping

the phone).

When the IC first senses the power supply input voltage it will delay

τ

If there is disconnect of the charge power supply, the IC will delay

τ

will ignore the interruptions of duration shorter than specified. These specs apply to the entire Normal Temperature Range.

20111505

FIGURE 2. V

www.national.com

7