DC Gain in switching-mode power supplies is defined as the (output voltage)/(input voltage) and is usually defined in terms of the duty cycle D and 1-D. D' is sometimes used for 1-D. For example, the DC Gain of a buck-boost converter would be expressed as D/(1-D) or D/D'. It is a dimensionless parameter and can have the values of zero to infinity. It is often non-linear.
The duty ratio D is the ratio of the on-time to the period, (on-time)/(on-time + off-time) of the power transfer switch when is is taking energy from the source. It is a dimensionless parameter that can have values between 0 and 1.
1-D or D' is the ratio of off-time to the period of the power transfer switch. It is a dimensionless parameter that can have values between 0 and 1.
The period is the sum of the on-time and off-time of the power transfer switch. Dimensions are time.
The switching-frequency is the reciprocal of the period. Dimensions are Hertz (preferred) or cycles-per-second.
Legal Statement
Do not use this information for design without independent verification of the information.
Copyright © 1992 - 2001 Jerrold Foutz
All Rights Reserved