The SMB135 is a programmable single-cell lithium-ion/lithium-polymer battery charger for a variety of portable applications. The device provides a simple and efficient way to charge high-capacity Li-Ion batteries via a USB port or an AC adapter. Unlike conventional devices, the SMB135’s high-efficiency operation eliminates large internal temperature rise and localized hot spot in handheld devices.
The SMB135 from Summit Microelectronics is a programmable single-cell lithium-ion/lithium-polymer battery charger for portable applications, providing a way to charge high-capacity Li-Ion batteries through a USB port or an AC adapter. It uses a high-efficiency current-mode PWM controller and 1% accurate output voltage regulation in a 1.3 x 2.1 mm uCSP-15 package.
Charge control includes qualification, trickle-charge, pre-charge, constant current/constant voltage and termination/safety settings that are fully programmable through a serial I2C/SMBus interface and non-volatile memory. Protection covers over-current, under/over-voltage and thermal protection, with the PWM switcher cutting back duty cycle as the junction temperature approaches about 145 °C; charge state and fault conditions can be monitored on the serial port or signaled by an LED driver output.
| Input voltage range | 4.35 to 6.0 V |
|---|---|
| Switching frequency | 750 kHz to 1.25 MHz |
| Output voltage regulation accuracy | 1% |
| Package | 1.3 x 2.1 mm uCSP-15, 0.4 mm pitch |
| Operating temperature range | -30 °C to +85 °C |
| Thermal cutback threshold | approximately 145 °C junction temperature |
| Battery type | Single-cell lithium-ion/lithium-polymer |
It operates from a 4.35 to 6.0 V input voltage range.
Its charge settings are fully programmable via a serial I2C/SMBus interface and non-volatile memory.
The fast charge current level (one or five unit loads) can be set via I2C or an input pin (USB500/100).
As the junction temperature approaches approximately 145 °C, the PWM switcher starts to cut back on the duty cycle to reduce current.