Overview: CN3387 is a PFM boost type multi-cell NiMH battery charge control integrated circuit operating at 2.7V to 6.5V, which can manage the charging of 4 to 12 NiMH batteries. CN3387 uses constant current mode and trickle charging mode to manage battery charging. It integrates a reference voltage source, inductor current detection unit, battery voltage detection circuit, and external field-effect transistor drive circuit, etc., with the advantages of fewer external components and simple circuit. When the input power is connected, CN3387 enters the constant current charging state, controlling the external N-channel MOSFET to turn on, the inductor current rises, and when it rises to the upper limit set by the external current detection resistor, the external N-channel MOSFET turns off, and the inductor current decreases, and the energy in the inductor is transferred to the battery. When the inductor current drops to the lower limit set by the external current detection resistor, the external N-channel MOSFET turns on again, and this cycle repeats. When the FB pin voltage reaches 1.125V (typical value), CN3387 enters the trickle charging mode. At this time, the input current is reduced to 66% of the constant current state, and the internal timer is started. When the internal timer ends or the FB pin voltage reaches 1.205V, the charging process ends, and the external N-channel MOSFET remains off. When the FB pin voltage drops to the recharge threshold (1.105V), CN3387 enters the charging state again. The maximum operating frequency of CN3387 can reach 1MHz, and the operating temperature range is from -40°C to +85°C. When the battery voltage is lower than the input voltage or the battery is short-circuited, CN3387 continues to charge the battery with a smaller current under the combined action of the external N-channel MOSFET and P-channel MOSFET, protecting the battery. Other functions include chip enable input and status indication output. CN3387 uses a 10-pin SSOP10 package.

Product Parameters

Main Functions: PFM boost type multi-section NiMH battery charging control integrated circuit

Operating Mode: Switching

Battery Type: Nickel-metal hydride battery

Number of Batteries: 1-11

Output Voltage Range: 0-18V

Input Voltage Range: 2.7V-6.5V

Operating Current: 300uA

Solar Power Supply: Yes

Thermal Modulation: No

Packaging Form: SSOP10

Maximum Output Power: 35W

Built-in Power Tube: No

Applications:

l Independent NiMH battery charger

l Power tools

l Toys

l Independent charger

Features:

l Input voltage range: 2.7V to 6.5V

l Operating current: 300μA @VIN=5V

l Inductor current detection

l Suitable for solar power applications

l Up to 1MHz switching frequency

l Maintain charging mode to ensure battery is full

l Timer ends charging

l Automatic recharging function

l Up to 35W output power

l Charges at a lower current when the battery voltage is lower than the input voltage or the battery is short-circuited.

l Adaptive function of input power supply

l Chip enable input

l Battery overvoltage protection

l Status indication output

l Operating temperature range: -40°C to 85°C

l 10-pin SSOP10 package

l Lead-free product, meets RoHS directive requirements, halogen-free