LM3655 datasheet(10/21 Pages) NSC

10 / 21 page

11.0 Charge Control Functions (Continued)

Unless otherwise specified, limits are for Normal Operating range.

Specification

Test Conditions

Min

Typ

Max

Units

Quiescent Current when charge power supply

is detected “I

Q_CHRG”

CELL ^ VPUV to VTERMX;VIN = 0; No Load at

Radio B+; CHRG_DETB, CHEMISTRY,

DISABLE, CHRG_STATE and CNTRL pins.

DETECT = 300 µA;

800

µA

Low Charge Voltage Threshold “V

CHRG_LOW”

@ T= 25˚C

Transition from Charge State High to Charge

State Low

2.50

2.575

2.65

Low Charge Voltage Threshold V

CHRG_LOW

(normal operating temperature range)

Transition from Charge State High to Charge

State Low

2.475

2.675

Maximum Trickle Charge Current

“I

TRICKLE-MAX” @ 25˚C range (current out of

CELL pin)

CELL = 3.5V, IDETECT = 1.250 mA, VPS =6V

190

Maximum Trickle Charge Current

“I

TRICKLE-MAX” - normal operating range

(current out of CELL pin)

CELL = 3.5V, IDETECT = 1.250 mA, VPS =6V

150

250

Minimum Trickle Charge Current “I

TRICKLE-MIN”

- normal operating range (current out of CELL

pin)

CELL = 3.5V, IDETECT = 12 mA, VPS = 27.5V

Maximum Sub 2V Charge Current

“I

SUB2V-MAX”- @ 25˚C (current into VIN pin

and out of CELL pin)

CELL = 1.1V, VPS = 6V (For 1V < VCELL

< 2V, I

SUB2V will monotonically increase)

37.5

Maximum Sub 2V Charge Current

“I

SUB2V-MAX” - normal operating range (current

into V

IN pin and out of CELL pin)

CELL = 1.1V, VPS = 6V (For 1V < VCELL

< 2V, I

SUB2V will monotonically increase)

12.5

Maximum Sub 2V Charge Current

“I

SUB2V-MAX”- @ 25˚C (current into VIN pin

and out of CELL pin)

CELL = 1.8V, VPS = 6V (For 1V < VCELL

< 2V, I

SUB2V will monotonically increase)

37.5

Maximum Sub 2V Charge Current

“I

SUB2V-MAX” - normal operating range (current

into V

IN pin and out of CELL pin)

CELL = 1.8V, VPS = 6V (For 1V < VCELL

< 2V, I

SUB2V will monotonically increase)

12.5

11.2.5 Full-Rate Charging

Once the cell voltage rises above V

PHONE_ON, the cell will be charged at full-rate unless the cell voltage drops below

CHARGE_LOW. The charge power supply will deliver all the charge current it can into the load while the IC is monitoring the power

dissipation of Q1 with the maximum of P

PASS_MAX and the maximum charge current of ICHRG-MAX. Should the power dissipation

of Q1 or the charge current exceed these limits, the IC will revert to trickle charge mode to protect Q1 from over-dissipation.

Q1 is saturated when the charge current is in full-rate and Q1 is operated in linear mode when the charge current is in trickle

charging mode. Because transient loads on Radio B+ (such as when the phone is in its pulsed transmit mode) can cause voltage

transients on the cell pin, it is determined that Q1 is NOT saturated ONLY after the peak detected Q1 emitter voltage minus the

cell pin’s voltage exceeds Q1

UNSAT for a debounce period of 8 ms. This debounce is applied to all uses of Q1UNSAT in the IC.

UNSAT is the voltage between the cell pin and the emitter of Q1, which corresponds to the voltage drop across M5 and the

saturation drop across Q1.

The CHRG_STATE output pin of the IC will change its state when V

CELL reaches VTERMX. It will not go high because Q1UNSAT

is exceeded.

Unless otherwise noted, the following specifications apply over the Normal Temperature Range.

Specification

Test Conditions

Min

Typ

Max

Units

Charge Control Voltage Threshold “V

TERMX”

“V

TERMX =VTERML” @ 25˚C

Chemistry Pin LOW

4.065

4.10

4.135

“V

TERMX =VTERMH” @ 25˚C

Chemistry Pin HIGH

4.13

4.16

4.19

“V

TERMH”– “VTERML” @ 25˚C

“V

TERMX =VTERML” 0˚C to +50˚C

Chemistry Pin LOW

4.03

4.17

“V

TERMX =VTERMH” 0˚C to +50˚C

Chemistry Pin HIGH

4.10

4.22

“V

TERMX =VTERML” −20˚C to +70˚C

Chemistry Pin LOW

3.90

4.25

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