| 摘要 |
<p>A three-wire dimmer comprises: a chopper switch (601), a chopper switch control circuit (602), an impedance matching circuit (604) and an impedance matching control circuit (603). The chopper switch control circuit (602) connects the chopper switch (601) and the impedance matching control circuit (603). When the chopper switch control circuit (602) controls the chopper switch (601) to be turned on, the dimmer outputs a network voltage, and at the same time, the chopper switch control circuit (602) sends a control signal to the impedance matching control circuit (603), so that the impedance matching control circuit (603) controls the impedance matching circuit (604) to assume high impedance. When the chopper switch control circuit (602) controls the chopper switch (601) to be turned off, the dimmer outputs a low level or a zero level, and at the same time, the chopper switch control circuit (602) sends a control signal to the impedance matching control circuit (603), so that the impedance matching control circuit (603) controls the impedance matching circuit (604) to assume low impedance. The impedance matching control circuit (603) in the dimmer is disposed inside the dimmer, and when one dimmer is cascaded with multiple loads, it is unnecessary to use multiple impedance matching circuits repeatedly, thereby reducing the volume of the circuit, and reducing the cost and power consumption.</p> |
