Power Management Unit for Imaging Modules

The ADP5020 provides a highly integrated power solution that includes all of the power circuits necessary for a digital imaging module. It comprises two step-down dc-to-dc converters, one LDO, and a power sequence controller. All dc-to-dc converters integrate power pMOSFETs and nMOSFETs, making the system simpler and more compact and reducing the cost. The ADP5020 has digitally programmed output voltages and buck converters that can source up to 600 mA. A fixed frequency operation of 3 MHz enables the use of tiny inductors and capacitors. The buck converters use a voltage mode, constant-frequency PWM control scheme, and the synchronous rectification is implemented to reduce the power loss. The Buck 1 regulator operates at up to 93% efficiency.

The ADP5020 provides high performance, reduces component count and size, and is lower in cost when compared to conventional designs.

The ADP5020 runs on input voltage from 2.4 V to 5.5 V and supports one-cell lithium-ion (Li+) batteries. The high performance LDO maximizes noise suppression. The ADP5020 can be activated via an I2C® interface or through a dedicated enable input. During logic-controlled shutdown, the input is disconnected from the output source, and the part draws 1 μA typical from the input source. Other key features include undervoltage lockout to prevent deep-battery discharge and soft start to prevent input current overshoot at startup. The ADP5020 is available in a 20-lead LFCSP.

APPLICATIONS

* Digital cameras, handsets

* Mobile TVs

* Input voltage range: 2.4 V to 5.5 V

* Low standby current: 1 μA

* Switching frequency: 3 MHz

* I2C interface

* Synchronous Buck 1 regulator: 600 mA

* Synchronous Buck 2 regulator: 250 mA