Author Topic: Is dc dimmer a dc buck coverter  (Read 318 times)

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Offline abdulbadii

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Is dc dimmer a dc buck coverter
« on: November 30, 2022, 11:53:51 am »
Is mostly market found dc dimmer a dc buck coverter ?
Anyone please generous enough elaborate its function circuit blocks

Offline Terry Bites

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Re: Is dc dimmer a dc buck coverter
« Reply #1 on: November 30, 2022, 12:19:16 pm »
For an LED dimmer?
This would be a controlled current source.

See a typical driver with circuit fucntions explained

Offline Siwastaja

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Re: Is dc dimmer a dc buck coverter
« Reply #2 on: November 30, 2022, 12:51:22 pm »
No idea. You would need to post an example of what you think is a "mostly market found dc dimmer", then we can guess.

Optimum way to drive LEDs is a constant-current power supply, which internally provides adjustable current, and has a control input. In such case the "dimmer" would be just a controller which drives the control input.

If the "dimmer" is a separate product which takes DC voltage in and then drives the LEDs, then it - at least hopefully - does constant current regulation and turns the non-optimal voltage based power supply into better-for-LED current source. Buck is a very likely topology to implement this.

Or, the separate dimmer could be something as simple as an adjustable resistor. Who knows, there is a lot of crap on the market.

Offline ajb

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Re: Is dc dimmer a dc buck coverter
« Reply #3 on: November 30, 2022, 03:28:58 pm »
A standalone "DC dimmer" designed for constant-voltage LED loads (for example 12V LED tape), if that's what you're talking about, is just PWM.  Its functional circuit blocks would include some sort of PWM signal generator (maybe a 555, maybe an MCU) and a transistor, that's about it.  If you added a second transistor or a diode (which might already be present if the dimmer was also designed for inductive loads like motors), an output inductor, and some feedback, then you'd have a buck converter. 

There are also dimmable LED drivers in both constant current and constant voltage mode variations that I suppose you could refer to as a 'DC dimmer'.  One of those that operates from a DC input might be a buck converter, but ones that operate off of AC line voltage likely use a different topology.
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