| 摘要 |
Radiotelephones often are powered by batteries (12). When a radiotelephone is bumped, the battery (12) can lose electrical contact with the radiotelephone. When power is interrupted (40), a timer is started (42). When the power is reapplied (44), the timer is sampled (46) and compared against a predetermined period of time. If the power was interrupted for a short time, then the radiotelephone is turned on (50). If the power was interrupted for a long time, then the radiotelephone stays off (48). The timer in the circuit is implemented as an RC circuit (26) starts to discharge. If the voltage level falls below Vref, the radiotelephone will not turn on when the power is reapplied. |
