Home > Flashlight 101 > Drivers
In the old days, you could touch two wires from a battery to a bulb and you had a flashlight...sort of. Now with LEDs, if you connect the emitter directly to a battery, you will have a flashlight, but only for a few seconds...then you're in the dark again.
LED flashlights require a driver to operate...a driver is a circuit board with the control logic chip and power regulators that actually send the power to the emitter. The MCU or logic chip will give instructions to the power regulators and the regulators do the real work. Using a Li-Ion battery is a real advantage because it has very high energy density and is rechargeable many times, but for safety, it requires a safety shutdown to prevent over discharging. The driver monitors the charge state of the battery and will warn you when it's getting low -then will shut down the light down after some time. All PFlexPRO flashlights have safety controls to monitor the charge state of the battery.

22 Mode Group Driver:

The is the workhorse of the PFlexPRO line...it allows any of 22 mode groups to be selected. A mode group is simply a set of modes...like: 'Low, Med, High'. When you set the flashlight for a particular mode group, it's the only mode group you will see...so operation is simple. If you set the mode group to 'L,M,H'...you will only have that group until you set a different group. To change from one mode group to the next, you simply press the switch 8 times quickly, pause, then press the number of times that corresponds to your desired group. Example: to change the flashlight to Mode Group 5 (L,H - Memory), simply press the switch quickly 8 times, pause about ½ second, then press 5 times, then pause and the flashlight will blink to confirm the change...after you change groups a few times, it's really easy.

Why So Many Mode Groups:
Well, more is better! From the 22 mode groups, it's easy to find the one(s) you really want. Some groups are ascending (L,M,H), and some groups are descending (H,M,L). Some mode groups have XLow (moonlight), some have as many as 5 levels, a few have flashy modes and one 'group' is high only. You don't need to remember the group numbers...most people find the one they like, set it and forget it. I have 2 groups I like...I will often swap between these 2 and I remember these two group numbers like I remember my anniversary...(sometime in April I think).

Some groups have 'Memory'...other groups have 'No Memory'...whats the difference?
Memory means, when you turn the flashlight off, the next time you turn it on, it will be in the mode you last used. No Memory means, when you turn the flashlight on, it will turn on in the first mode of the group. With No Memory, if you choose a mode group like XL,L,M,H, the flashlight will always turn on in XL mode. This driver has off-time memory...okay, this may sound a little confusing, but the good thing is you don't need to understand it...it just works well. Offtime Memory means the memory mode doesn't set until the flashlight is turned off for about ½ second. The reason this is really nice...as long as the flashlight is on, the driver is waiting for your next half press to change to the next mode.

High Mode Step Down (aka Turbo Step Down)
The 22 mode driver has an adjustable Step Down that will reduce the output to a lower level after some amount of time. The amount of time is adjustable. This is a nice feature for the very high power units...using this feature will greatly extend the run-time. When the light steps down, it does it slowly over a period of 5 seconds...you will hardly notice it. I will ship each flashlight set to the recommended step down time. You will receive an output graph for your flashlight and will see the step down.

Battery Level:
Have you ever pick up your flashlight and had no idea if the batteries were okay. This driver allows you to check the charge (voltage) of the battery. You simply press the switch 8 times quickly (as if you're going to change the mode group), the flashlight will begin to flash...each flash is .1 volt. The count doesn't start at zero volts, it starts at 3 volts. If the flashlight flashes 5 times...then the battery is at 3.5v. (each flash is counting up by .1v starting at 3V so 5 flashes would be: 3.1, 3.2, 3.3, 3.4, 3.5v).

Mode Lock:
Some flashlights (mainly P60) have small contacts showing through the potting material. If you want to lock your selected mode group, just paint the contacts with conductive paint. Even though, accidentally changing the mode group would be difficult, this would make it impossible (until you scraped off the paint).

Mode Groups:
Selectable Mode Groups:
1. 2%-25%-100% -| Memory
2. 100%-25%-2% -| No Memory
3. 2%-25%-100%-Strobe-Beacon -| Memory
4. 2%-25%-100%-Strobe-Beacon -| No Memory
5. 15%-100% -| Memory
6. 100%-15% -| No Memory
7. 100% Only
8. 100%-Strobe -| No Memory
9. Strobe-100% -| No Memory
10. ML-5%-33%-100% -| Memory
11. 100%-33%-5%-ML -| No Memory
12. ML-5%-33%-100%-Strobe-Beacon -| Memory
13. ML-5%-33%-100%-Strobe-Beacon -| No Memory
14. ML-100% -| No Memory
15. 100%-ML -| No Memory
16. ML-100% -| Memory
17. ML-5%-15%-50%-100% -| Memory
18. ML-5%-15%-50%-100% -| No Memory
19. 100%-50%-15%-5%-ML -| Memory
20. 100%-50%-15%-5%-ML -| No Memory
21. 2%-15%-50%-100% -| Memory
22. 2%-15%-50%-100% -| No Memory

To change mode groups, press the switch 8 times quickly, pause, then press the
number that corresponds with the desired mode group
(complete instructions will be included)

Advance Program Driver (Direct Drive):

Gobs of Mode Groups: If 22 mode groups aren't enough, then how about over 16 billion? With the AP driver built into your flashlight, that's how many unique mode groups you can create. You will have the ability to have as few as 1 mode or as many as 7 modes in each group. You can change the intensity of each mode to any of 24 different intensity levels. If you like, you can turn any mode into a strobe, beacon or bike mode and adjust the intensity of these special modes. You can start in medium, then high, then low...or anything you want.

Active Thermal Control:
The AP driver has Active Thermal Control -this feature alone is worth the added cost. The Active Thermal control will maintain a selected temperature by adjusting the output in very small, hardly noticeable increments. This is important in case someone 'borrows' your light and decides to run it in Turbo continuously, of if you lay the light down without the benefit of using your hand as a heat sink. If you want a P60 with direct drive capability, the Active Thermal Control will keep your emitter safe. Still, Direct Drive shouldn't be over used -it will suck the life out of your battery quickly.

Triple Power Channels:
The AP driver has 3 separate power channels. One channel is dedicated to the lower output range...this means the firefly and moonlight modes can be very low and very stable. The second channel handles the mid to upper regulated power levels. The third channel is dedicated to the direct drive modes. Since the direct drive modes have their own power channel, the light can have direct drive modes and fully regulated modes.

Selectable Memory:
After building your mode group, you can decide what type of memory you want and assign it to that mode group -no memory, standard memory or hybrid memory.

Hidden Mode:
Each mode group has one hidden mode that is accessed by a double tap of the switch. This is a great place to store rarely used modes that you still want available (strobe, beacon, bike mode) or program it with Full-Turbo (direct drive). That way, if your mode group starts in lower modes, you can quickly jump to Turbo.

Low Voltage Protection:
The AP driver monitors the battery voltage and when low, it will reduce the power level by half. The power reduction will cause the battery voltage to rebound and continue running. When the voltage drops again, the power will reduce 1/2 again...it will continue this cycle so you're not completely left in the dark because of a dead battery. Even though you will not have full output, 'some light is always better than no light'.

Mode Lock:
You can pick any mode in your groups and lock that mode so it becomes a single mode flashlight and still preserve the mode group settings.

Program Lock:
Once you have everything set the way you want it, you can lock the programming. Since you use the same switch sequence to check the voltage of the battery, the Program Lock ensures that you will not alter your settings while checking the battery.

Bump Proof:
If mounted on a bike, bumps may cause the battery to loose contact for a very short moment...the AP driver ignores the brief power interruptions and maintains the current mode.

The AP Driver is capable of direct drive... not all emitters are compatible with direct drive. Because of the low vF, a single Nichia emitter will pull too much current in the direct drive mode and will damage the emitter. The Cree XPL2 is another emitter with low vF and should not be used in the direct drive mode. If you want to use the AP driver with either a single Nichia or XPL2, emitter -do not program direct drive (step 24) as one of your levels. Multiple Nichia and XPL2 emitters are safe to use in the direct drive mode, although they will generate a lot of heat.

Advance Program Driver (Regulated):

The Advance Program - Regulated driver has all the features of the Advance Program - Direct Drive, but the final 2 steps are fully regulated.
The ultimate power level of these 2 highest modes vary depending on the host and emitter, but the following lights typically have the AP-R driver set at 4.9A: P60, P60+Solarforce, Convoy S2+. For the M1 and C8, the max current is set for 4.56A. While the L2 can be built with the AP-R driver, the L2's high mass and huge battery capacity is perfectly happy running the AP- Direct Drive.

There are several situations where this fully regulated driver is the best choice:

Emitter Restrictions: The Nichia emitters can safely be used with the AP-Regulated driver in a single emitter setup. A single Nichia emitter should not be used with a Direct Drive Driver. This also applies to any emitter with a very low forward voltage, such as the Cree XPL2 emitters.

Triples: If you've had experience with a triple emitter light, you know heat can be an issue... even with thermal control. A triple mounted in a small host such as the S2+ will get hotter faster than the thermal regulation can handle. That's why I recommend not using step 24 in a triple or only using it for very short periods. With the AP-R driver, a triple can have regulation in all modes and in addition, the thermal regulation has no problem managing the heat. Although, the AP-R driver will not reach the very high initial outputs of a direct drive triple, it will deliver more light after the first minute of run time.

General Flashlight Use: While the direct drive mode is incredibly bright (initially), the output is reduced as the battery drains... keep in mind that the battery drains from the first moment the light is turned on. The AP-Regulated driver will maintain constant current to the emitter until the battery can no longer supply sufficient voltage at a given power level. Many people prefer a flashlight where all modes are regulated as long as the higher modes are bright enough- running at 4.5A, it's definitely bright enough.

Crescendo Driver:

Crescendo Firmware was developed by BLF's Toykeeper. The Crescendo Firmware is loaded onto a FET (direct drive) + 7135 (single regulator) driver. The FET will allow extreme brightness while the single 7135 will support a very low moonlight mode. This driver doesn't have a mode group with individual modes. Instead, the flashlight will ramp up and down and you choose the brightness you want at any given time. If you enable memory, the light will return to the last brightness level you used. If you want to ramp up to a brighter level, just tap the switch... for lower levels, double tap the switch. You can also access the moonlight mode or turbo mode without going through the ramping sequence.
All of this may sound complicated, but it's not: from off turn the light on... it will start ramping up and down... half press and it stops. If memory is enabled, when you turn it on, it will resume the last brightness level. One half press and it will ramp up -half press again and it will stop -or- double half press and it will ramp down... another half press and it will stop.
This makes it easy to choose the level you're looking for because there are no preset brightness levels... just ramp up or down and choose.
You can also access special modes (turbo strobe, bike mode, low power strobe and battery indicator), turn memory on or off and adjust the thermal control.

The Crescendo Driver is capable of direct drive. Since the Crescendo firmware does not have static, programmable steps, I do not offer this driver with a single Nichia or XPL2 emitter. With the AP driver, you can choose not to program in direct drive. Because Crescendo ramps to direct drive in normal operation, there is no way to defeat the direct drive option.

The Crescendo Driver uses free software developed by BLF's Toykeeper.
Source code for Toykeeper's Crescendo is available here.
The general user's interface is shown below: