SGM4056
Standalone linear Li-ion battery charger with 1A programmable charge current and automatic recharge functionality
Product Overview
Description
The SGM4056 is a complete constant-current/constant-voltage linear charger for single-cell lithium-ion batteries.
With up to 1A programmable charge current, it is ideal for portable applications powered by USB or AC adapters.
The device automatically terminates charge when complete and monitors battery voltage for recharge.
Product Series
SGM
Primary Application
Portable media players
Key Features
- Complete linear charger for single-cell Li-ion
- Up to 1A programmable charge current
- No external MOSFET or blocking diode needed
- USB/AC adapter compatibility
- Automatic recharge threshold
- Charge status output
- Soft-start limits inrush current
- Thermal regulation protection
Specifications
| Input Voltage | 4.3V to 6.5V |
|---|---|
| Battery Voltage | 4.2V (fixed) |
| Charge Current | Up to 1A (programmable) |
| Trickle Charge | 130mA (typ) |
| Quiescent Current | <2mA (charging) |
| Standby Current | <55μA |
| Charge Accuracy | ±1.5% |
| Package | SOT-23-5, ESOP-8 |
Applications
Portable media players
Electronic system design
Bluetooth headsets
Electronic system design
Smart watches
Electronic system design
Portable medical devices
Medical electronics
Power banks
Electronic system design
FAE Expert Insights
"The SGM4056 is my standard recommendation for single-cell Li-ion charging applications up to 1A. The standalone operation requires minimal external components - just a resistor to set charge current and a capacitor for stability. The thermal regulation feature is particularly useful - it automatically reduces charge current if die temperature exceeds 120°C, preventing overheating in thermally constrained designs. I've used this part in countless portable device designs with excellent reliability. The charge status output is simple but effective - it drives an LED directly for visual indication. For USB-powered applications, set charge current to 500mA or less to comply with USB specifications. The automatic recharge feature maintains battery capacity by topping off the charge when voltage drops below 4.05V. Overall, an excellent linear charger solution."
Simple, reliable linear Li-ion charger with minimal external components and excellent thermal management
— Dr. Michael Chen, BeiLuo
Frequently Asked Questions
What is the maximum charge current of SGM4056?
The SGM4056 supports up to 1A charge current, programmed by an external resistor. For USB applications, limit to 500mA. For AC adapter applications, up to 1A is possible with proper thermal management.
Set charge current based on your power source capability and thermal constraints.
How do I set the charge current on SGM4056?
Charge current is set by a resistor connected to the PROG pin. The formula is Ibat = 1000/Rprog. For 500mA, use 2kΩ. For 1A, use 1kΩ. The resistor should be 1% tolerance for accurate current programming.
Calculate Rprog = 1000/Ibat. Use 1% tolerance resistor for accurate current setting.
What is the charge status output on SGM4056?
The CHRG pin provides charge status: low (LED on) during charging, high impedance (LED off) when charging complete. It can directly drive an LED with current limited by external resistor. The CHRG pin provides visual indication of charging status. Connect an LED with appropriate current limiting resistor to VCC for visual charge indication.
Connect LED with 1kΩ-10kΩ resistor to VCC for visual charge indication.
Does SGM4056 have thermal protection?
Yes, SGM4056 includes thermal regulation that reduces charge current if die temperature exceeds 120°C. This prevents overheating and allows maximum charging within thermal constraints. This feature allows safe charging in thermally constrained designs without requiring external thermal management or heat sinks.
Thermal regulation allows safe charging in thermally constrained designs without external thermal management.
Can SGM4056 charge from USB?
Yes, SGM4056 can charge from USB 5V supply. For USB compliance, set charge current to 500mA or less using Rprog ≥ 2kΩ. The device works with both USB and AC adapter inputs. The device works with both USB and AC adapter inputs. Higher currents require AC adapter with adequate current capability and proper thermal design.
Use 500mA max for USB compliance. Higher currents require AC adapter with adequate current capability.