D2Flex Technical

TASKLED - Smart LED drivers

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Discontinued (use lFlex instead)

25 Jan 2010: New UI-UNI2 firmware released. Instruction manual is here d2flex V2 manual.

The Instruction manual for D2Flex with UI-UNI (prior to 25 Jan 2010) is here d2flex.pdf

D2Flex is 0.80" (nominal) in diameter. An external momentary action switch (normally open) must be provided by the customer.

The following block diagram shows how to connect the battery and LED(s) to the D2Flex driver.

Battery input voltage can be from 2.7V to 24V (max).

SW+ and SW- (SW- is electrically the same as IN-) are provided to enable a momentary action (normally open) switch to be connected to d2Flex to control its operation. The switch only switches a control signal and carries at most 300microamps.

The FET switch (that controls power to the LED) is rated at a nominal 6A. This means up to 6A of LED load can be connected to the D2Flex driver.

NOTE 1: The D2Flex driver is a PWM direct drive controller. It does not regulate current or limit current, thus it is the user's responsibility to ensure the current to the LED(s) is limited externally. This may require either a series resistor or an external current regulator.

NOTE 2: The user should measure the Vf of each LED at the rated current. For example, if using four P7 LEDs, measure each Vf at 2.8A and sum the total Vf (lets assume they are 3.4, 3.5, 3.3 and 3.4 for this example, so the total is 13.6V). Then take the fully charged battery voltage (typically 4 li-ion cells) of 4.2 x 4 = 16.8V. Calculate the necessary resistor as below:

(16.8V - Total_Vf) = (16.8V - 13.6V) = 3.2V

Next we calculate the necessary resistance we need to add:

V = I x R, or R = V / I

3.2V / 2.8A = 1.2 ohms

Without adding in the 1.2 ohm resistor in series with the P7's, the initial current when the batteries are fresh off the charge will potentially be much greater than the current rating of the FET (3.4A) and the FET can be damaged.

Below is a picture of the back side of the board ( MOSI, MISO and RST pads/holes must be left unconnected, they are used during board manufacture to program/configure the board). V1.2 connections are the same as V1.1 shown below.