New member and I just purchased a Zebra light h51. What is the difference in these two modes, and what will they do to my battery (will pwm run my battery completely flat?) Sorry If this an old question but I tried the search function and but I couldn't find anything. Thanks in advance. Joe
Regulated Vs PWM
- Thread starter JoeA
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tolkaze
Enlightened
Regulation and PWM only partly go together. Regulation generally means that the output will be relatively steady until the battery is depleted, then either shut off or rapidly dim then shut off. This allows maximum run-time at a given output level.
Non-regulated lights start off bright, and get dimmer for each output level as the battery depletes.
Regulation normally uses a buck / boost driver set up to keep the power (current?) to the LED at a constant level and effects the output from the battery to the LED. PWM afaik, effects the output from the driver to the LED, changing the perceived brightness.
PWM is a method of maintaining a lower level than full output, by rapidly turning the light on and off. At say 70% brightness, it will be turning on and off hundreds of times a second, at 5% brightness, this could be a lot less frequent.
So really, to answer your question, PWM doesn't have much to do with running the battery completely flat. No more than say... running it on a level with no PWM. the terminating voltage should be about the same
Non-regulated lights start off bright, and get dimmer for each output level as the battery depletes.
Regulation normally uses a buck / boost driver set up to keep the power (current?) to the LED at a constant level and effects the output from the battery to the LED. PWM afaik, effects the output from the driver to the LED, changing the perceived brightness.
PWM is a method of maintaining a lower level than full output, by rapidly turning the light on and off. At say 70% brightness, it will be turning on and off hundreds of times a second, at 5% brightness, this could be a lot less frequent.
So really, to answer your question, PWM doesn't have much to do with running the battery completely flat. No more than say... running it on a level with no PWM. the terminating voltage should be about the same
Without getting too technical...
Regulation can be in both voltage or current (power) forms. PWM is a method to perform regulation (not a type of regulation). PWM stands for Pulse Width Modulation. In a switch mode power supply (SMPS), the frequency is typically held constant while the width of the pulses vary. Varying the pulse width changes the average voltage (or current, depending on the regulation type) that the LED sees and thus changes the LED's output. There's been an inaccurate method of describing PWM and current regulation on CPF for a few years now. Again, PWM is not a type of regulation, but a method to perform that regulation. Current regulation simply uses a feedback circuit that senses the load current and adjusts the voltage to maintain the same load current.
The regulator topologies used (words that like to thrown around like buck, boost, and buck/boost) depends on the battery source. Most lights that use a single cell (i.e. 1xAA, 1x123, etc.) use a boost circuit only to increase (boost) the voltage to that required by the LED. When a voltage that's higher than the LED voltage is used (i.e. Li-Ion cell), the boost circuit is bypassed and the driver runs in direct drive mode (with the resistive loss associated with the output stage). Some lights use buck/boost which essentially is both driver types on a single board to provide regulation regardless of input voltage (within the driver's limitations). Larger lights that use multiple cells use buck circuits which reduce voltage to that of the LED's operation voltage (Vf).
Hope this helps clarify some of the driver terminology and inner workings for you.
Regulation can be in both voltage or current (power) forms. PWM is a method to perform regulation (not a type of regulation). PWM stands for Pulse Width Modulation. In a switch mode power supply (SMPS), the frequency is typically held constant while the width of the pulses vary. Varying the pulse width changes the average voltage (or current, depending on the regulation type) that the LED sees and thus changes the LED's output. There's been an inaccurate method of describing PWM and current regulation on CPF for a few years now. Again, PWM is not a type of regulation, but a method to perform that regulation. Current regulation simply uses a feedback circuit that senses the load current and adjusts the voltage to maintain the same load current.
The regulator topologies used (words that like to thrown around like buck, boost, and buck/boost) depends on the battery source. Most lights that use a single cell (i.e. 1xAA, 1x123, etc.) use a boost circuit only to increase (boost) the voltage to that required by the LED. When a voltage that's higher than the LED voltage is used (i.e. Li-Ion cell), the boost circuit is bypassed and the driver runs in direct drive mode (with the resistive loss associated with the output stage). Some lights use buck/boost which essentially is both driver types on a single board to provide regulation regardless of input voltage (within the driver's limitations). Larger lights that use multiple cells use buck circuits which reduce voltage to that of the LED's operation voltage (Vf).
Hope this helps clarify some of the driver terminology and inner workings for you.
tolkaze
Enlightened
Thank you for the quick answers:wave:
I found your forum about three weeks ago, and so far it's cost me:
- Zebralight H51w
- Klaurus ST 20
- Maha charger & eneloops
Its so cold in the Doghouse
Yup, its an addiction!
![hellokitty[hk]](https://data.www.candlepowerforums.com/avatars/m/24/24229.jpg?1627508792){kind=avatar}
hellokitty[hk]
Enlightened
- Joined
- Jan 29, 2007
- Messages
- 645
At least you'll be able to see throughout the nightThank you for the quick answers:wave:
I found your forum about three weeks ago, and so far it's cost me:
- Zebralight H51w
- Klaurus ST 20
- Maha charger & eneloops
Its so cold in the Doghouse
.
