drphil69
Member
Hello!
I have an application that uses an H-Bridge PWM output to drive an amplifier card on an hydraulic valve. After much testing, we figured out that the amplifier card is responding to the PWM switching frequency, which is 4000 Hz. Therefore, it needs an analog signal - the easiest thing to do is put in a simple RC filter circuit, actually 2 circuits (one for each side of the H-Bridge). I was wondering if there is an easier way to do this? For example, what would happen if instead of 2 separate RC circuits, I used just one capacitor between the 2 H-Bridge outputs (after the resistors, one on each output)? I want to keep this as simple as possible, as I need a good time response.
Any help or ideas would be greatly appreciated. I learned a lot from an early post about using an RC filter to convert PWM to analog.
My understanding of an H-Bridge is that it is a power supply output whose poles can be rapidly changed, i.e. +V wire can be rapidly switch with ground thus giving the appearance of +/-V with a supply that only puts out +V.
My system: 12 volt supply (PWM), need +/-10V generated by H-Bridge, PWM frequency = 4000 Hz, minimal current draw.
Thanks!
I have an application that uses an H-Bridge PWM output to drive an amplifier card on an hydraulic valve. After much testing, we figured out that the amplifier card is responding to the PWM switching frequency, which is 4000 Hz. Therefore, it needs an analog signal - the easiest thing to do is put in a simple RC filter circuit, actually 2 circuits (one for each side of the H-Bridge). I was wondering if there is an easier way to do this? For example, what would happen if instead of 2 separate RC circuits, I used just one capacitor between the 2 H-Bridge outputs (after the resistors, one on each output)? I want to keep this as simple as possible, as I need a good time response.
Any help or ideas would be greatly appreciated. I learned a lot from an early post about using an RC filter to convert PWM to analog.
My understanding of an H-Bridge is that it is a power supply output whose poles can be rapidly changed, i.e. +V wire can be rapidly switch with ground thus giving the appearance of +/-V with a supply that only puts out +V.
My system: 12 volt supply (PWM), need +/-10V generated by H-Bridge, PWM frequency = 4000 Hz, minimal current draw.
Thanks!
