Power and Clocking

Figure 8-5. Example Form Factor Reference Design Power System Design

 

 

LDO

Audio AMP

 

 

 

ON/OFF

 

 

 

 

 

 

 

LDO

Audio_DC3P3V

 

 

 

ON/OFF

 

 

 

LDO

 

 

 

MMC_VDD

ON/OFF

 

LDO

LCD_DC3P3V

 

3.3V

 

ON/OFF

 

 

 

LDO

 

 

 

 

ON/OFF

 

LCD_DC5V

 

LDO

 

 

 

 

ON/OFF

 

 

 

 

3.2V

 

 

 

 

 

 

LDO

LCD_DC4V

 

 

 

ON/OFF

 

 

 

 

 

LDO

 

 

LCD_DC15V

 

ON/OFF

 

 

CF_VDD

 

 

 

3.3V

 

 

 

 

 

 

Boost

LCD_DC14V-

 

 

 

Converter

 

 

 

 

 

 

 

MAX633

 

 

Boost

 

 

LCD_DC11P7V-

 

 

 

 

 

Converter

 

 

 

 

LTC1308A

DC_5P5V

 

 

 

 

LDO

 

 

 

 

3.2 V

 

 

 

LDO

 

 

DC_3P3V

 

 

 

 

 

3.3 V

 

 

 

 

 

DC_CORE

 

 

 

Buck

0.8 - 1.3 V

 

 

 

Converter

 

 

 

LTC1878

 

 

 

Wall

Battery

 

 

 

Input

 

DC_PLL

 

Charger

 

 

Current

 

LDO

 

LTC1730

 

1.3 V

 

Limited

 

 

battery

 

 

 

 

 

 

 

8.7.2CORE Power

The example form factor reference design has a variable 0.8 V – 1.3 V core power supply for the applications processor. This voltage varies depending on the performance required by the application. A Linear Technologies LTC1878 buck converter is chosen for this application. The power is drawn directly from the Li+ battery. This device operates at 550 kHz and can supply up to 1 A at 0.8 V and 800 mA at 1.3 V with up to 95% efficiency. The device is turned on/off by the SA_PWR_EN signal directly from the applications processor.

The required output voltage is statically adjusted by selecting the value of the feed-back resistor. Ultimately, output voltage can be changed using software control of the Linear Technologies LTC1663 DAC. This DAC is controllable via the standard I2C bus, and can modify the voltage of the feedback path of the buck converter, which effects a change in the output voltage.

8.7.3PLL Power

DC_PLL supplies power to the three PLLs within the applications processor. This pin requires a 0.85 V to 1.3 V nominal supply at an expected 20 mA load.

8-22

PXA250 and PXA210 Applications Processors Design Guide

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Intel PXA250 and PXA210 manual Core Power, PLL Power

PXA250 and PXA210 specifications

The Intel PXA250 and PXA210 processors, part of the Intel XScale architecture, were introduced in the early 2000s, targeting mobile and embedded applications. They are known for their low power consumption, high performance, and advanced multimedia capabilities, making them suitable for a wide range of devices, including PDAs, smartphones, and other portable computing devices.

The PXA250, which operates at clock speeds ranging from 400 MHz to 624 MHz, features a superscalar architecture that allows it to issue multiple instructions per clock cycle. This enhances the overall performance for demanding applications while maintaining low power usage. It supports a variety of peripheral interfaces, including USB, Ethernet, and various memory types, which contributes to its versatility in different product designs.

One of the key technologies in the PXA250 is the integrated Intel Smart Repeat Technology, which optimizes data processing, thereby reducing the amount of power consumed during operation. This feature is particularly important for battery-powered devices, as it extends the overall battery life, allowing for longer usage times in mobile environments. Additionally, the PXA250 includes a dedicated graphics acceleration unit, which enables enhanced graphics and multimedia performance suited to modern applications at the time.

In contrast, the PXA210 is a more entry-level processor, aimed at cost-sensitive applications. Operating at lower clock speeds, typically around 200 MHz to 400 MHz, it forgoes some of the advanced performance features of the PXA250 while still offering a good balance of performance and power efficiency. The PXA210 is less complex, making it suitable for simpler devices that do not require the extensive capabilities of the PXA250.

Both processors utilize the Intel XScale architecture, which is based on the ARM instruction set. They are built on a 0.13-micron process technology, enabling higher density and lower power consumption compared to their predecessors. With integrated memory controllers and bus interfaces, they facilitate efficient data handling and connectivity options.

In summary, both the Intel PXA250 and PXA210 processors played a crucial role in the evolution of mobile computing by providing powerful processing capabilities with energy efficiency. Their features and technologies enabled device manufacturers to create innovative products that catered to the growing demand for portable devices during that era.