5V to 1.5V conversion

[ajsivsan]

Hi,

I am in need of a circuit to do the following scenario.

I have a coil in my circuit. It has to be operated in 5V for 60 seconds. Then it must be operated in 1.5V for 90 seconds. This must be happening continuously. I have a microcontroller in my circuit. So the timing issuce can be solved with the controller. But the problem is i need 1.5V and switching between the voltages. If any one has and idea please share with me. It shouldn't be a complicated circuit. Since my PCB is almost complete and i am not in a position to add more components.

Thanks
Siva.

 

[colin55]

Simply provide two outputs. One directly to the solenoid and the other via a 3v6 zener or a set of signal diodes.

 

[peufeu]

Use PWM to modulate the voltage.

 

[Diver300]

I agree with Peufeu. Your coil should have to have a freewheel diode, and if you turn on the supply for 30% of the time, the current will be much the same as if the voltage were to be 1.5 V. The inductance of the coil will keep the current from changing much between the on and off parts of the PWM.