| 摘要 |
<p>A power supply for driving one or more low voltage LED strings from a higher voltage ac or do supply also provides a dimming capability, either by direct variation of the input supply or independently of the input supply by a simple internal controller. The power supply comprises at least two conversion stages, a first conversion stage 101 comprising input terminals 100 for connection to an ac or do supply, a high frequency resonant converter with constant output current characteristics and output terminals 102 for connection to at least one second conversion stage 111. Each second conversion stage comprises a current multiplier circuit and output terminals 112 for connection to a load. The power supply does not require current feedback in order to obtain acceptable current regulation, even under significant changes in the LED voltage or the number of LEDs in a string. The power supply can drive one or more LED strings from a single power supply without the need to individually monitor the current in each string.</p> |
