REV 1.1

6

TEMP input Current

0.5

uA

Pin

Sink Current

10

mA

Leakage

Current

1

uA

Detailed Description

CN3082 is a mutli-chemistry battery charge control chips for single cell lithium batteries, lithium iron phosphate

and single or two to four nickel-metal hydride batteries. The device contains an on-chip power MOSFET and

eliminates the need for the external sense resistor and blocking diode. CN3082 is specifically designed to work

within USB power specifications.Continuous charge current can be programmed up to 600mA with an external

resistor.

The on-chip 8-bit ADC can adjust charging current automatically based on the output capability of input power

supply, so CN3082 is ideally suited for the solar-powered systems, or the applications that need to charge battery

with an input power supply whose output capability is limited.

The internal thermal regulation circuit reduces the programmed charge current if the die temperature attempts to

rise above a preset value of approximately 115℃. This feature protects the CN3082 from excessive temperature,

and allows the user to push the limits of the power handling capability of a given circuit board without risk of

damaging the CN3082 or the external components. Another benefit of adopting thermal regulation is that charge

current can be set according to typical, not worst-case, ambient temperatures for a given application with the

assurance that the charger will automatically reduce the current in worst-case conditions.

The charge cycle begins when the voltage at the VIN pin rises above the UVLO level, The

pin outputs a

logic low to indicate that the charge cycle is in precharge or constant current charge mode. At the beginning of

the charge cycle, if the voltage at FB pin is below 1.54V, the charger is in precharge mode and charging current

is set by constant current of 20% .The charger goes into the fast charge constant current mode once the voltage

CN3082 goes into the Continuous charge mode once the voltage on the FB pin rises above 2.445V, the maintain

charging current is determined by the input voltage VIN, RISET and RIMIN(as finger 1),.

pin assumes a

high impedance state. In maintaining charge mode, when the battery voltage feedback input FB pin voltage

drops to 1.65V, CN3082 will begin a new charge cycle, into the pre-charge mode or constant-current charging

mode. Of course, the input voltage can also be off, then power on to start a new charge cycle. On-chip precision

voltage reference and comparator circuit to ensure constant current charge voltage accuracy within 1%, to meet a

variety of rechargeable batteries. When the input voltage is not present, the charger goes into a sleep mode,

dropping battery drain current to less than 3uA. This greatly reduces the current drain on the battery and

increases the standby time. The charging process shown in Figure 3: