MagicShine 1400 Deconstructed
Процитирую весь пост целиком. Кто не знает английского, воспользуйтесь гугл-транслейтом
I got my hands on a MS1400 and am in the process of analyzing how the electronics work. I'll do a more complete post shortly with pictures and details, but here's a sneak peak at some of the more interesting details.
The circuit board in the center section of the light housing contains two complete switching buck current regulators. One for the main light and one for the side lights. The driver for the side lights is set for a base drive current of 0.6 amps and the one for the main light is 2.4 amps. The board in the main housing is just the base regulators; it doesn't provide any of the logic for user control of the light.
The command control button provides all the user control for the light. It's connected to the driver pcb via a four wire cable. Two of the wires are power and ground and the other two carry pulse width modulated (PWM) control signal for the main and side lights. This pcb basically has a microcontroller, a button, some LEDs for the battery status, and a voltage regulator.
As I suspected, the PWM control signals to the light are never driven at 100% (constant on) even when the light is on its highest setting. The duty cycle is in the 95% range when the lights are on high. It is interesting that the high setting for main and side lights is the same 95% regardless of whether the two sets of LEDs are on individually or together. That means in theory that the drive current to the main LED should be the same whether it's on by itself on combined with the side lights. This is different from what was implied by the current measurements odtexas posed earlier. I think the electrical noise from having both drivers running may have caused low readings when both sets of LEDs were on.
So is it bad that the lights are never on 100% of the time... Not necessarily. In theory that means the max average current for the main P7 LED should be 95% of 2.4 amps and 95% of the 0.6 amps for the side LEDs. In practice, that may not be true because it depends on how long it takes the driver to ramp back up to full power after being off for an instant.
It does mean that you won't get accurate current measurements for the LEDs with a normal multimeter. The current flow in this case isn't technically DC due to the PWM and most multmeters won't give an accurate measure of the true average current for a switched waveform. It's actually quite difficult to get good numbers for a circuit like this. Switching regulators generate a lot of electrical noise, which makes it hard to get accurate reading even using an oscilloscope. And these drivers are definitely on the noisy side. It's good they are inside a metal housing because they would certainly cause problem for other wireless accessories if they were in a plastic case. That may still be an issue, but it's not something I've tried.
Here is what I measure for power consumed from the battery at different light levels.
Side lights (high) - 4 watts
Main Light (high) - 8.3 watts
Both (high) - 12.3 watts
I'm still trying to get precise measurements for the LED currents. It looks to be less than 95% of the base current settings for the drivers. From preliminary data, it looks like the true average current is about 90% of 2.4 and 0.6 amps for the main and side LEDs. If that’s correct, that puts the average LED currents at
P7 LED current on high - 2.2 amps
XPE LED current on high - 0.55 amps
Based on the datasheets for the LEDs and 90% efficiency of optics, I would estimate the light output as:
P7 Main Light - 550 lumens
XPE Side Lights - 300 lumens
Total - 850 lumens
All these numbers are preliminary and I will update them as I get more detailed measurements. One thing I'm still investigating is whether the electrical noise when both drivers are running is actually messing up the efficiency of the drivers and hence the output or if it's mostly just causing causing problems with getting accurate measurements.
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Сообщение от ZaRtin
Так что тут всё адекватно. 
