LED torch using MAX660

Description: This is a simple LED torch circuit based on the MAX660 integrated circuit from MAXIM semiconductors. The MAX660 is a CMOS monolithic voltage converter IC capable of driving three bright white LEDs connected in parallel to output pin 8. The circuit is designed for good battery life, and the switch S1 functions as a push-to-ON switch. However, LEDs may not illuminate even with a 3V supply due to varying dropout voltages among different LEDs, with white LEDs requiring a higher forward bias voltage than 3V. The MAX660 can generate -3V from the supply at pin 5, resulting in a voltage difference of 6V across pins 5 and 8, which is sufficient to activate the LEDs.

The LED torch circuit utilizes the MAX660 voltage converter to efficiently power multiple LEDs. The MAX660 is designed to convert a lower voltage into a higher voltage, making it suitable for applications where the supply voltage is insufficient to drive high-brightness LEDs. In this configuration, the circuit is powered by a battery that provides a nominal voltage of 3V.

The connection of three white LEDs in parallel ensures that they share the total current supplied by the IC, allowing for uniform brightness. The choice of a push-to-ON switch (S1) enables the user to easily control the operation of the torch, providing convenience in its usage.

It is essential to note the importance of the forward voltage drop characteristic of the LEDs used in the circuit. White LEDs typically require a forward voltage of approximately 3.0 to 3.6V to turn on, which means that the circuit must provide sufficient voltage to overcome this threshold. The MAX660's ability to generate a voltage difference of 6V between pins 5 and 8 ensures that the required forward voltage is met, allowing the LEDs to operate effectively.

In summary, this LED torch circuit exemplifies an efficient design leveraging the capabilities of the MAX660 voltage converter to drive bright white LEDs. The configuration ensures good battery life while maintaining optimal performance, making it a practical solution for portable lighting applications.This is a simple LED torch circuit based on IC MAX660 from MAXIM semiconductors. The MAX 660 is a CMOS type monolithic type voltage converter IC. The IC can easily drive three extra bright white LEDs. The LEDs are connected in parallel to the output pin 8 of the IC. The circuit has good battery life. The switch S1 can be a push to ON switch. @Taimu r, Led`s may not glow even in 3V supply! Cause different LED`s Have different drop out voltage( The minimum forward bias voltage to turn the LED on). For white LEDs, it`s higher than the 3V. Max 660 can derive -3V from the supply at pin5. so in the circuit, across the pin 5 and 8, a voltage difference of 6V is available. It`s sufficient to turn on the LED and glow it!