AIC1782CS 查看數據表（PDF） - Analog Intergrations

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AIC1782CS

Dual-Battery Charge Controller

Analog Intergrations 

The AIC1782 provides the function of dis-

charge-before-charge to precondition NiCd

batteries which suffer from memory effect. This

function can only be activated for pack B after

the prequalification of battery voltage and tem-

perature, yet before the charge completion is

registered for fast charge cycle of pack B.

To trigger this function, DSW pin has to be bi-

ased to GND over 0.18 second. After discharge

begins, LEB1 and LEB2 pins are both OFF,

ICOB pin is ON, and DIS pin goes high to acti-

vate an external circuit to discharge the battery

pack B until the voltage of BBV pin fall below

0.9V (or 0.69V, depending on the input voltage

of SEL3 pin) or DSW pin is biased to GND for

over 0.18 second again. The application circuit

is included in TYPICAL APPLICATION

CIRCUIT.

Fast Charge

After the battery passes fault checks, charge

begins on either of the batteries, the other bat-

tery remains in a waiting state until the first bat-

tery terminates fast charge. The AIC1782 will

automatically switch to fast charge the second

battery. The battery pack A has the priority over

battery pack B only when power is first applied

to the AIC1782. When fast charging begins, the

initial and safety timer of the AIC1782 start

counting. Functions of -∆V detection, Peak volt-

age timer, ∆T / ∆t detection, and maximum

battery voltage are, however, disabled tempo-

rarily until the initial timer period in the initial

stage of a charge cycle elapses. The initial timer

period is equal to 1/80 of safety timer.

Since the low limit of acceptable ABV or BBV

voltage are only about 0.16V during the initial

timer period, even deeply discharged batteries

can easily qualify to be fast charged subse-

quently.

AIC1782

In the course of fast charge, the AIC1782 con-

stantly monitors the battery voltage and tem-

perature through ABV (or BBV) and ATS (or

BTS) pins. The fast charge process is regis-

tered complete when any one of the following

situations is encountered, which are explained

below:

Negative delta voltage (-∆V).

Peak voltage timer (0∆V ).

Delta temperature/ delta time (∆T / ∆t ).

Maximum charge time.

Maximum battery voltage.

Maximum battery temperature.

-∆V Cutoff

The AIC1782 makes a voltage sampling at ABV

(or BBV) pin every 4 seconds when safety timer

period is set equal to 80 minutes. If a negative

delta voltage of 0.25% compared to its peak

value is detected at ABV (or BBV) pin, the fast

charge cycle is terminated.

0∆V Cutoff

If the battery voltage stays at its peak value or

decreases very slowly for the duration deter-

mined by the peak voltage timer, which is in turn

equal 3.7% of safety timer, the fast charge ac-

tion is terminated.

∆T/∆t Cutoff

The ∆T / ∆t detection of the AIC1782 is per-

formed by sensing the decrease of ATS (or BTS)

pin voltage in a specific timer interval dictated

by the safety timer. The fast charging termi-

nates when the decrease of ATS (or BTS) pin

voltage in 56 seconds exceeds the predeter-

mined value set by ADJ pin input. This time in-

terval of 56 seconds is based on the assump-

tion that voltage of ATS (or BTS) pin is sampled

once for every 8 seconds, which is also deter-

mined by safety timer.

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