You need an inductor as well as a PWM circuit to form a buck converter.
How are you igniting the lamp? Normally this requires a high voltage so you need to be sure the components you select can withstand the ignition voltage.
I have an ignition module that will take care of the start pulse. It is a series triggering scheme with an RF component to it.
The lamps require "resonably clean" DC to operate. Most of the PWM stuff I see is related to inverter stuff or simulating a waveform.... I want low ripple D.C. so I assume I want a high freq. drive.
I am having trouble understanding the difference in regulation schemes using PWM for constant- voltage/current/power control.
I assume I need two circuits- one to adjust current and one to adjust voltage?
I am under the assumption that I would need to use the PWM circuit for the current regulation part- and to adjust the voltage, I would regulate the voltage into the switching devices?
This is confusing me, I "somewhat" understand the implications of Ohm's law and I see how
changing the duty cycle of the pulses changes the average voltage seen by the load as well as limits the power per unit time the load receives. so when I adjust the PW will I not be changing both the voltage and the current seen by the load?
How do I keep one constant while adjusting the other and visa-versa?
Any good tutorials or books to recommend?
Thanks again for the time to help
Dave V.