The RT5021 is a complete power supply solution for digital still cameras and other hand held devices. The RT5021 is composed of a multi-channel DC/DC power converter unit, a single-cell linear Li-ion battery charger, a charger type detector, and an I2C control interface.
The power converter unit includes one synchronous step-up converter (CH1), one synchronous step-up/down converter (CH2), three synchronous step-down converters (CH3/4/5), two LDOs with input power as low as 1.5V (CH6/8), one WLED driver in synchronous high-voltage step-up mode or low-voltage current regulator mode (CH7), and a keep-alive LDO (CH9) for RTC application. All converters are internally frequency compensated and integrate power MOSFETs. The power converter unit provides complete protection functions : over current, thermal shutdown, over voltage, and under voltage protection. RT5021 has a WAKEUP impulse generation circuitry to monitor VIN or BAT installation event. To fulfill most of applications, RT5021 has six preset power on/off sequences.
The battery charger includes Auto Power Path Management (APPM). No external MOSFETs are required. The charger can enter sleep mode when power is removed. Charging tasks are optimized by using a control algorithm to vary the charge rate, including pre-charge mode, fast charge mode and constant voltage mode. The charge current can also be programmed via the I2C control interface. The battery regulation voltage and current can be adjusted by JEITA standard temperature control or other schemes set via the I2C interface. The internal thermal feedback circuitry regulates the die temperature to optimize the charge rate for all ambient temperatures. The charging task will always be terminated in constant voltage mode when the charging current reduces to the termination current of 10% x ICHG_FAST. The charger includes under voltage and over voltage protection for the supply input voltage, VIN. The charger includes USB charger detection circuitry via D+ and D- pins of USB interface to detect USB standard downstream ports (SDP), USB charging downstream port (CDP), dedicated charger port (DCP), or Apple/Sony charger ports. RT5021 uses some indicators to show charger states : two open drain ports CHG and CHG2, and an interrupt (INT) to immediately notify the state change.
RT5021 has I2C interface to control rich functions of Power Converter Unit and Charger Unit. The RT5021 is available in the WQFN-40L 5x5 package.
Applications
- DSC Power Supply System
- CMOS-Sensor DV
- Portable Instruments