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ADP5301は2.15 V ~ 6.50 Vの入力スタートアップ電圧範囲で動作するので、複数のアルカリ、NiMH、リチウム電池、その他の電源ソースを使用することができます。出力電圧は外部VID抵抗と工場出荷時のフューズによって0.8 V ~ 5.0 Vの範囲で選択可能です。この回路は全部で4個の小型の外付け部品しか必要としません。
The ADXL345 is a small, thin, low power, 3-axis accelerometer with high resolution (13-bit) measurement up to ±16 g. Digital output data is formatted as 16-bit twos complement and is accessible through either an SPI (3- or 4-wire) or I2C digital interface.
The ADXL345 is well suited for mobile device applications. It measures the static acceleration of gravity in tilt-sensing appli-cations, as well as dynamic acceleration resulting from motion or shock. Its high resolution (4 mg/LSB) enables measurement of inclination changes of about 0.25°. Using a digital output accelerometer such as the ADXL345 eliminates the need for analog-to-digital conversion, reducing system cost and real estate. Additionally, the ADXL345 includes a variety of built-in features. Activity/inactivity detection, tap/double-tap detection, and free-fall detection are all done internally with no need for the host processor to perform any calculations. A built-in 32-stage FIFO memory buffer reduces the burden on the host processor, allowing algorithm simplification and power savings. Additional system level power savings can be implemented using the built-in activity/inactivity detection and by using the ADXL345 as a “motion switch” to turn the whole system off when no activity is felt and on when activity is sensed again.
The ADXL345 communicates via I2C or SPI interface. The circuits described in this document demonstrate how to implement communication via these protocols.
Figure 1. ADXL345 and ADuC7024 in 4-Wire SPI Configuration (Simplified Schematic: Decoupling and All Connections Not Shown)
Figure 2. ADXL345 and ADuC7024 in I2C Configuration (Simplified Schematic: Decoupling and All Connections Not Shown)
The circuit shown in Figure 1 is a complete low cost, low power, mono audio amplifier with volume control, glitch reduction, and a 3 W Class-D output driver.
The volume is controlled manually with a simple push-button interface to a 64-position digital potentiometer. An automatic store function retains the last volume setting, and an LED provides visual information of the maximum/minimum volume.
The SSM2375 Class-D driver amplifier provides up to 3 W output power into 3 Ω load, with 93% power efficiency at 5 V, built in pop and click suppression, and shutdown mode.
The circuit provides a preconditioning input stage, allowing compatibility with a wide range of audio input signals and can be powered with a cell battery.
Figure 1. Audio Volume Control (Simplified Schematic: Decoupling and All Connections Not Shown)