3V供电的LED驱逐舰电路 (3V LED Chaser)

General

There are many 9V chaser circuits that seem to waste about 7V when driving LEDs that are height=485 src="/data/attachment/portal/201007/ET29904201007211358411.jpg" width=735 border=0>

Specifications
• Battery: Two alkaline cells (AA size were used in the prototype)
• Battery Life: AA cells C cells D cells
Minimum speed and brightness 8 months 2 years 4.9 years
Medium speed and brightness 6 months 1.5 years 3.6 years
Maximum speed and brightness 2 weeks 1.5 months 3.6 months
• Stepper speed: 2 LEDs/sec to 2 revolutions/sec
• Brightness: Controlled with Pulse Width Modulation, from very dim to 161mcd (very bright)
• Pulse Width Modulation frequency: 1.4KHz very bright to 6KHz very dim
• LED current: 15mA pulses, reduced to 10.5mA at maximum Pulse Width Modulation
• LED voltage drop: 1.76V (measured, not rated) @ 10.5mA
• Minimum battery voltage (total of both cells): <1.24V, circuit is running but LEDs are not lit
1.6V, LEDs are very dim at maximum brightness
2.0V, LEDs reach almost full brightness, battery replacement is recommended.
• Radio interference: None

Circuit Description
The 74HC Cmos ICs are rated for a 2V to 6V power supply for high-speed logic circuits. They continue to operate at a much lower voltage but no longer meet high-speed logic specifications. To reach high speeds, their output current can momentarily exceed 400mA (low voltage drop) but thermal considerations limit maximum continuous output current to 20mA. Perfect for driving LEDs!

• IC2 is a 10 stage Johnson counter/decoder. height=480 src="/data/attachment/portal/201007/ET29904201007211358412.jpg" width=639 border=0>