Controller manages multiple power domains

Dialog Semiconductor has launched a general purpose device for use as a core building block in power management subsystems in portable electronics equipment, cellular handsets and digital cameras.

Dialog Semiconductor has launched a general purpose device for use as a core building block in power management subsystems in portable electronics equipment, audio players, cellular handsets and digital cameras.

The new DA9025 high performance power management controller takes a system level approach to managing the multiple power domains and voltage requirements of lithium powered portable applications, integrating a number of functions and interfacing directly with a battery pack.

Containing four low power, high performance, low dropout regulators based on Dialog Semiconductor's unique 'Smart MirrorT' technology, a real-time clock supply and a high efficiency buck convertor, the new IC fits between the simple single function device such as a low dropout regulator (LDO) or switching convertor, and sophisticated system-on-chip ICs.

The main benefit of this approach is that it reduces the cost and PCB overhead of having to build in multiple off-the-shelf, low-integration power management components from multiple vendors.

The DA9025 can be used both stand-alone with pre-determined power-up sequence for simple operation, or controlled by an I2C bus for greater control and programmability of output voltages and power in individual blocks.

Power efficiency and therefore longer battery life is enabled using Dialog Semiconductor's patented and unique Smart MirrorT architecture - a technology that optimises quiescent current consumption by matching it to the current demand and performance required, removing the need for a low power mode and the associated hardware and software overhead.

Typical handheld applications for the DA9025 include those with a lithium power source, processor controlling the main functionality, memory, external peripherals such as a display, memory expansion, such as SD or MMC card and some analogue functionality such as data conversion or sensor interfacing.

Such a system requires a number of different power domains.

For example, the processor may typically require two supplies, a low voltage for its core to save power consumption and higher voltage to interface with the other devices.

Analogue functions tend to require higher voltages to guarantee operating headroom or provide powerful output drivers, and display drivers tend to require higher voltages as display size and complexity increases.

The DA9025's low dropout voltage regulators are designed specially for supplying stable voltages to various parts of the system.

The low drop linear regulators are optimised for critical system parameters such as low noise, high power supply rejection or low quiescent current.

Two of the LDOs may be used to supply audio or RF circuits as they are low noise and typically exhibit more than 80dB power supply rejection.

Battery supplies to the regulators are separated to maximise isolation.

Under I2C control the regulator output voltage is also programmable.

A fifth integrated regulator provides a supply for a real-time clock.

This is permanently active when the battery is connected but is a very low quiescent current design.

The integrated DC/DC buck convertor has a programmable range of 0.85 to 3.3V, with a default supply of 1.8V at up to 400mA.

In many systems the buck convertor is used to power the system processor and memory.

The buck convertor may be set to operate in either synchronous or asynchronous modes to optimise operating efficiency depending on load current.

The convertor has integrated switching FETs and requires a minimum number of external components.

Under I2C control the buck convertor output voltage is also programmable allowing very low voltage processors to be used.

The DA9025 is available now in a 4 x 4mm 24 QFN package.

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