LTC4099EPDC-PBF View Datasheet(PDF) - Linear Technology

Part Name

Description

MFG CO.

LTC4099EPDC-PBF

I2C Controlled USB Power Manager/Charger with Overvoltage Protection

Linear Technology 

LTC4099

Typical Performance Characteristics TA = 25°C, VBUS = 5V, BAT = 3.8V, RPROG = 1.02k,

RCLPROG = 3.01k, unless otherwise noted.

Battery Charge Current and

Voltage vs Time

5

1.0

4

0.8

3

0.6

500mA

2

0.4

1

CHARGER TERMINATION 0.2

4-HOUR SETTING

0

0123456

TIME (HOURS)

VBUS INPUT LIMIT SET FOR 790mA

BATTERY CHARGER SET FOR 500mA

FLOAT VOLTAGE SET FOR 4.2V

0

78

4099 G34

Output Voltage vs Battery Voltage;

Battery Charger Overprogrammed

4.4

BATTERY CHARGER SET FOR 1200mA

Suspend LDO Transient Response

(500µA to 1.5mA)

4.2

4.0

500mA USB

SETTING

3.8

3.6

100mA USB

3.4

SETTING

IOUT

500µA/DIV

0mA

VOUT

20mV/DIV

AC-COUPLED

3.2

3.0

2.4

BATTERY VOLTAGE

2.7 3.0 3.3 3.6 3.9 4.2

BATTERY VOLTAGE (V)

4099 G35

500µs/DIV

4099 G36

Pin Functions

OVGATE (Pin 1): Overvoltage Protection Gate Output.

Connect OVGATE to the gate pin of an external N-channel

MOSFET pass transistor. The source of the transistor should

be connected to VBUS and the drain should be connected

to the product’s DC input connector. In the absence of an

overvoltage condition, this pin is driven from an internal

charge pump capable of creating sufficient overdrive to

fully enhance the pass transistor. If an overvoltage condition

is detected, OVGATE is brought rapidly to GND to prevent

damage to the LTC4099. OVGATE works in conjunction

with OVSENS to provide this protection.

NTC (Pin 2): Input to the Negative Temperature Coefficient

Thermistor Monitoring Circuit. The NTC pin connects to

a negative temperature coefficient thermistor which is

typically copackaged with the battery to determine if the

battery is too hot or too cold to charge. If the battery’s

temperature is out of range, charging is paused until the

battery temperature re-enters the valid range. A low drift

bias resistor is required from NTCBIAS to NTC and a

thermistor is required from NTC to ground.

NTCBIAS (Pin 3): NTC Thermistor Bias Output. Connect a

bias resistor between NTCBIAS and NTC, and a thermistor

between NTC and GND.

10

VC (Pin 4): Bat-Track Auxiliary Switching Regulator Control

Output. This pin drives the VC pin of an external Linear

Technology step-down switching regulator. In conjunction

with WALL and ACPR, it will regulate VOUT to maximize

battery charger efficiency.

WALL (Pin 5): Auxiliary Power Source Sense Input. WALL

is used to determine when power is available from an

auxiliary power source. When power is detected, ACPR is

driven low and the USB input is automatically disabled.

BATSENS (Pin 6): Battery Voltage Sense Input. For proper

operation, this pin must always be connected to BAT. For

best operation, connect BATSENS to BAT physically close

to the Li-Ion cell.

PROG (Pin 7): Charge Current Program and Charge Current

Monitor Pin. Connecting a resistor from PROG to ground

programs the charge current. If sufficient input power

is available in constant-current mode, this pin servos

to one of eight possible I2C controllable voltages (see

Table 3). The voltage on this pin always represents the

actual charge current by using the following formula:

IBAT

=

VPROG

RPROG

• 1030

4099fd

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