CN3158

CN3158 is a charge management IC designed specifically for charging single-cell LiFePO4 batteries from input power sources with limited current output capability, such as solar panels. The internal power transistor performs constant-current and constant-voltage charging of the battery. The charge current is set by an external resistor, with a maximum continuous charge current of up to 1A, eliminating the need for an external blocking diode or current sense resistor. CN3158 integrates an adaptive charge current module that automatically adjusts the charge current based on the current output capability of the input power source. Users do not need to design for worst-case conditions — the charge current can be set according to the maximum current output capability of the input source, making full use of its available current capacity. This makes CN3158 ideal for charging applications powered by sources with limited current output, such as solar panels. CN3158 includes two open-drain status indicator outputs: a charging status indicator and a charge complete indicator. The internal power management circuit automatically reduces the charge current when the junction temperature exceeds 130°C, allowing users to maximize the IC's power handling capability without concern for overheating damage to the IC or external components. As a result, users can design the charge current based on typical conditions rather than worst-case scenarios, since CN3158 will automatically reduce the charge current under worst-case conditions. When the input voltage exceeds both the undervoltage lockout threshold and the battery voltage, CN3158 begins charging the battery and the pin outputs a low level, indicating that charging is in progress. If the voltage at the battery voltage sense pin (FB) is below 70% of the constant-voltage charge voltage, CN3158 trickle-charges the battery as a precondition. When the FB pin voltage exceeds 70% of the constant-voltage charge voltage, CN3158 charges the battery in constant-current mode, with the charge current set by resistor RISET connected between the ISET pin and GND. As the FB pin voltage approaches the constant-voltage charge voltage, the charge current gradually decreases and CN3158 enters constant-voltage mode. When the battery voltage reaches the constant-voltage charge voltage and the charge current decreases to the charge termination threshold, the charge cycle ends: the pin enters high-impedance state and the pin outputs a low level, indicating that the charge cycle is complete. The charge termination threshold is 10% of the constant-current charge current. To initiate a new charge cycle, simply power off and then power on the input source. In the charge complete state, a new charge cycle starts automatically when the charge current rises above 30% of the constant-current charge current. The high-precision internal voltage reference, error amplifier, and resistor divider network ensure that the constant-voltage charge voltage accuracy is within ±1%, meeting battery requirements. When the input voltage is lost or falls below the battery voltage, CN3158 enters a low-power sleep mode, with battery terminal current consumption of less than 3µA, thereby extending standby time.

Applications

• Solar chargers
• Applications charging via solar panels
• Applications with limited input power current output capability
• Emergency lighting
• Portable applications
• Various chargers

Key features

• Integrated adaptive charging current module that automatically adjusts charging current based on the current output capability of the input voltage source
• Compatible with limited-current voltage sources such as solar panels
• Input voltage range: 4.4V to 6V
• On-chip power transistor
• No external blocking diode or current sense resistor required
• Constant voltage charging at 3.63V, adjustable upward via an external resistor
• Can be used as a voltage source
• Internal soft-start circuit
• Trickle charge mode at low battery voltage to activate deeply discharged batteries and reduce power consumption
• Configurable continuous constant current charging up to 1A
• CC/CV/constant temperature charging mode to maximize charging current while preventing overheating
• Automatic entry into low-power sleep mode upon power supply voltage dropout
• Dual status indication outputs for charging and end-of-charge states
• C/10 end-of-charge detection
• Automatic recharge
• Battery temperature monitoring
• Package: eSOP8
• Lead-free, RoHS compliant, halogen-free