Application 1: Wiring in accordance with the following figure, use a suitable screwdriver gently and slowly rotate the adjustable resistance.
Application 2: Adjust the adjustable resistance to 0 ohms (or maximize the current according to Application 1) and then use the MCU output PWM signal to control the LED output current
the frequency of the PWM signal should be less than 2KHz
LD1500SB is a current regulation integrated circuit operating from an input voltage of 2.9V to 6.1V, the constant output current can be set up to 1.5A with an external resistor. The LD1500SB consists of high precision reference voltage, amplifier, current mirror, etc. The on-chip power transistor and current sense block greatly reduce the external component count, which makes the LD1500SB ideal for LED driver.
When the EN pin is high, the input voltage is greater than 2.9V, and is larger than the LED forward voltage plus the required voltage drop, LD1500SB functions normally to deliver constant current from the LED pin.
The LD1500SB adopts the temperature regulation instead of temperature protection function, the temperature regulation can make the LED being turned on continuously in case of high ambient temperature or high voltage drop. When the LD1500SB junction temperature reaches about 135 ° C, the internal temperature regulation block reduces the LED current so that the junction temperature will not rise any more. This feature allows the users to maximize the use of the power handling capability of the chip, do not worry about the chip overheating and damage to the chip or external components.
The LD1500SB also has the chip enable function, which can shutdown the whole chip to limit the current consumption within 1uA.
The LD1500SB also adopts the over current protection block. When LED current approaches 0.9A(Typical), the over current protection block begins to function to prevent the LED current from increasing further.
