Comments on: Design a Unipolar to Bipolar Converter for a Unipolar Voltage Output DAC http://MasteringElectronicsDesign.com/design-a-unipolar-to-bipolar-converter-for-a-unipolar-voltage-output-dac/ Electronics Design and Modeling with Emphasis on Analog Design Sat, 04 Feb 2012 22:03:02 +0000 http://wordpress.org/?v=2.9 hourly 1 By: Adrian S. Nastase http://MasteringElectronicsDesign.com/design-a-unipolar-to-bipolar-converter-for-a-unipolar-voltage-output-dac/#comment-5320 Adrian S. Nastase Sat, 04 Feb 2012 22:03:02 +0000 http://masteringelectronicsdesign.com/?p=944#comment-5320 You can do it both ways. First, you need to check what is the maximum allowed voltage in the input of the following stage. If you choose to limit the signal with the power supply, take into consideration what is the maximum output trip of the op amp. An op amp output cannot go to the power supply level, unless it is a rail-to-rail op amp. Then set your power supplies, both positive and negative accordingly. If you choose to limit the output with zener diodes, the limiting value will be the zener voltage plus 0.6V, which is the forward voltage of the other zener diode. When limiting, the current through the diodes will be limited by op amp, usually at a current between 10 to 15 mA, depending on its short circuit specs. Therefore, you need to check what is the zener voltage at that current to use the correct part. You can decrease the current by inserting a small resistor between the op amp output and the diodes. You can use this resistor only if the following stage input impedance is high enough so that the limiting resistor does not count. You can do it both ways. First, you need to check what is the maximum allowed voltage in the input of the following stage. If you choose to limit the signal with the power supply, take into consideration what is the maximum output trip of the op amp. An op amp output cannot go to the power supply level, unless it is a rail-to-rail op amp. Then set your power supplies, both positive and negative accordingly.

If you choose to limit the output with zener diodes, the limiting value will be the zener voltage plus 0.6V, which is the forward voltage of the other zener diode. When limiting, the current through the diodes will be limited by op amp, usually at a current between 10 to 15 mA, depending on its short circuit specs. Therefore, you need to check what is the zener voltage at that current to use the correct part. You can decrease the current by inserting a small resistor between the op amp output and the diodes. You can use this resistor only if the following stage input impedance is high enough so that the limiting resistor does not count.

]]> By: Gabriel http://MasteringElectronicsDesign.com/design-a-unipolar-to-bipolar-converter-for-a-unipolar-voltage-output-dac/#comment-5285 Gabriel Mon, 30 Jan 2012 20:10:49 +0000 http://masteringelectronicsdesign.com/?p=944#comment-5285 Hello I like the solution but I gess: If I have a signial to swing from 0V to 5V and need to convert it to -2.5 to +2.5V, I limit the output using a supply of +/-3V? or limit the out with 2 zener face to face? I cant figure it, could you help me? Regards Hello I like the solution but I gess: If I have a signial to swing from 0V to 5V and need to convert it to -2.5 to +2.5V, I limit the output using a supply of +/-3V? or limit the out with 2 zener face to face? I cant figure it, could you help me?
Regards

]]> By: Adrian S. Nastase http://MasteringElectronicsDesign.com/design-a-unipolar-to-bipolar-converter-for-a-unipolar-voltage-output-dac/#comment-3778 Adrian S. Nastase Mon, 04 Jul 2011 16:59:34 +0000 http://masteringelectronicsdesign.com/?p=944#comment-3778 You choose a reference voltage based on the input and output range. You gave me the input range, but I need the output range as well to give you advice. 230V? Is it DC? Sounds a lot for an Op Amp that usually works at maximum 36V. My point is, make sure that the voltage level that reaches the Op Amp is within it's operating limits. You choose a reference voltage based on the input and output range. You gave me the input range, but I need the output range as well to give you advice. 230V? Is it DC? Sounds a lot for an Op Amp that usually works at maximum 36V. My point is, make sure that the voltage level that reaches the Op Amp is within it’s operating limits.

]]> By: math http://MasteringElectronicsDesign.com/design-a-unipolar-to-bipolar-converter-for-a-unipolar-voltage-output-dac/#comment-3777 math Mon, 04 Jul 2011 08:43:25 +0000 http://masteringelectronicsdesign.com/?p=944#comment-3777 if the range of my input is 0-230 V. what should be the reference voltage?? if the range of my input is 0-230 V. what should be the reference voltage??

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