ST3S01LED View Datasheet(PDF) - STMicroelectronics

Part Name

Description

MFG CO.

ST3S01LED

BATTERY CHARGE I.C.

STMicroelectronics 

ST3S01LED

I.C. BLOCK DIAGRAM

POSSIBLE OPERATING MODES

Five different operating modes are allowed:

charge, precharge, reverse, charge+reverse and

precharge+reverse. These operating modes can

be achieved by properly selection of the

CMD-REVERSE CMD-PWM and CMD-MODE

(See POSSIBLE OPERATING MODE Table).

PRECHARGE MODE

The PRECHARGE function is composed by a

switch and a 100mA current source which fully

works for VCHARGE higher than 2.5V. When the

CMD-MODE and the CMD-PWM are not leaded

the switch is ON, being the input states held by an

internal pull down resistor. This is used when the

4/17

battery is strongly discharged. In this case VBATT

can be null (battery empty) and all the input pins

are not held by any level (because the

micro-controller is down), except the VCHARGE pin

which is a main supply. The source of current

supplies a constant current into the battery till its

voltage level reaches the required level allowing to

start the micro-controller (typically 3V). The

current direction is from VCHARGE to VBATT. The

reverse leakage current when the swich is ON

must be null; this is obtained thanks to an internal

circuitry that switch OFF the internal P-MOS when

the VBATT is higher than VCHARGE, whatever the

status of the CMD-MODE. The precharge function

is also used to adjust the mean current. When the

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