| 摘要 |
A crystal oscillator circuit has a sleep mode of operation that reduces power consumption while maintaining oscillation to provide for a fast transition to a normal mode of operation. The oscillator comprises current mirror coupled current sources (30,32,34). The first (30) and second (32) provide current to a first (16) and a second (22) amplifier. The third current source (34) is in normal mode coupled to a normal mode biasing current source (36) and in sleep mode to a bleeder resistor(40). In normal mode the amplifier (16,22) receives a large, normal mode current determined by the normal mode biasing current source (36). In the sleep mode a very small current sufficient for manforming the oscillation of the crystal oscillator is applied to the first amplifier (16). This current is determined by the bleeder resitor (40). The second amplifier (22) is shutdown because it is coupled to ground. <IMAGE>
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