Confused on flashlight voltage boost circuitry

[BT132435]

Hey all, so i'm a little confused about how a flashlight's voltage boost circuitry works. Lets say for example, a 1xAA LED flashlight. If the purpose of the circuitry is to boost the battery's supplied voltage to the LED's required voltage, then how does using a battery with higher voltage make the light brighter? Won't the Circuitry just maintain the supplied voltage to whatever the LED needs? I'm wondering because i just bought some NiZn batteries for my MiNi AA. How would the 1.6v from these batteries be better than the 1.2v from NiMh batteries because of the circuitry?

 

[rx78gp02]

yes pretty much

 

[PeaceOfMind]

Generally speaking, the closer the input voltage is to the output voltage, the less power is lost. i.e. it is more efficient to step 2 V to 3V than it is to step 1V to 3V with the same circuit.

 

[HKJ]

Won't the Circuitry just maintain the supplied voltage to whatever the LED needs? I'm wondering because i just bought some NiZn batteries for my MiNi AA. How would the 1.6v from these batteries be better than the 1.2v from NiMh batteries because of the circuitry?

That depends on the circuit, many boost circuits for 1.5 volt does not maintain voltage, but draws a fixed amount of current. I.e. higher voltage means more power to the led.

Note: Using LiIon is another case, there the voltage is high enough to bypass the boost circuit and directly drive the led, only limited by the resistance in the circuit.

 

[BT132435]

That depends on the circuit, many boost circuits for 1.5 volt does not maintain voltage, but draws a fixed amount of current. I.e. higher voltage means more power to the led.

Note: Using LiIon is another case, there the voltage is high enough to bypass the boost circuit and directly drive the led, only limited by the resistance in the circuit.

Ohhh current regulation, that makes a lot of sense actually. Thank you!

 

[HKJ]

Ohhh current regulation, that makes a lot of sense actually. Thank you!

If you are interested in the regulation, you can check the recent reviews on my website, many of them contains a voltage/current/lumen graph, that shows how the current changes with the voltage.

Here is en example from the Preon:

 

[DM51]

Moving this to the Batteries/electronics section...