LTC4101 查看數據表（PDF） - Linear Technology

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LTC4101

Smart Battery Charger Controller

Linear Technology 

LTC4101

OPERATION

Controlled Charging Algorithm Overview

The following conditions must be met in order to allow

controlled charging to start on the LTC4101:

1. The ChargingVoltage() AND ChargingCurrent() function

must be written to non-zero values.

2. The SafetySignal must be RES_COLD, RES_IDEAL, or

RES_UR.

3. AC must be present. This is qualified by DCDIV > VACP.

The following conditions will stop the Controlled Charging

Algorithm and will cause the Battery Charger Controller

to stop charging:

1. The ChargingCurrent() AND ChargingVoltage() func-

tions have not been written for TTIMEOUT.

2. The SafetySignal is registering RES_OR.

3. The SafetySignal is registering RES_HOT.

4. The AC power is no longer present. (DCDIV < VACP)

5. ALARM_INHIBITED is set in the ChargerStatus()

function.

6. INHIBIT_CHARGE is set in the ChargerMode() function.

Clearing INHIBIT_CHARGE will cause the LTC4101 to

resume charging using the previous ChargingVoltage()

AND ChargingCurrent() function values.

7. RESET_TO_ZERO is set in the ChargerMode() function.

8. CHGEN pin is pulled low by an external device. The

LTC4101 will resume charging using the previous

ChargingVoltage() AND ChargingCurrent() function

values, if the CHGEN pin is released by the external

device.

9. Insufficient DCIN voltage to charge the battery. The

LTC4101 will resume charging using the previous

ChargingVoltage() AND ChargingCurrent() function

values, when there is sufficient DCIN voltage to charge

the battery.

10.Writing a zero value to ChargingVoltage() function.

11.Writing a zero value to ChargingCurrent() function.

The SafetySignal Decoder Block

This block measures the resistance of the SafetySignal and

features high noise immunity at critical trip points. The low

power standby mode supports only battery presence SMB

charger reporting requirements when AC is not present.

The SafetySignal decoder is shown in Figure 4. The value

of RTHA is 1.13k and RTHB is 54.9k.

SafetySignal sensing is accomplished by a state machine

that reconfigures the switches of Figure 4 using THA_SELB

and THB_SELB, a selectable reference generator, and two

comparators. This circuit has two modes of operation

based upon whether AC is present.

VDD

RTHA

1.13k

16

THA

THA_SELB

VDD

RTHB

54.9k

15

THB

CSS RSafetySignal

THB_SELB

MUX

+

–

HI_REF

+

REF

–

LO_REF

SafetySignal

CONTROL

RES_OR

LATCH

RES_COLD

RES_H0T

RES_UR

TH_HI

TH_LO

4101 F04

Figure 4. SafetySignal Decoder Block

4101fa

17

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