| 摘要 |
<p>A battery charger comprising a converter (CNV) for converting an input voltage (Ui) which is connected between an input terminal (1) and a reference terminal (GND) into a terminal voltage (Vk1) of a rechargeable battery (BT) which is connected between an output terminal (2) and the reference terminal (GND). The converter comprises a first and a second switch (SW1, SW2), a coil (L), a control circuit (CNTRL), a comparator (CMP), a frequency counter (CNT), and an indicator (IND). If the terminal voltage (Vk1) is lower than the reference voltage (VRF), the start signal (ST) delivered by the comparator (CMP) will turn logic high. As a consequence the control circuit (CNTRL) will start an energy transfer cycle for transferring an amount of energy from the input terminal (1) to the rechargeable battery (BT). The frequency of the start signal (ST) decreases as the terminal voltage (Vk1) increases. By measuring the frequency of the start signal (ST) the indicator (IND) has the possibility of supplying a battery-high indication signal (BTHGH) when the rechargeable battery (BT) is almost full.</p> |
