spbhu
Member level 2
For dual supply, (e.g. Vdd=-Vss), the output DC level is normall set to zero, for maximum swing purpose. And of course the DC current to the load is zero if no input signal is applied.
However, for single supply case, (Vss=0), the output DC level is normally set to Vdd/2 for maximum swing, it seems the DC current to the load is quite large even no input signal is applied. For example, Vdd/2=1.5v, Rload=50Ω, then Iload=30mA even without signal input ?
What's the problem? Does it mean for drving a low load we always use dual supply?
Anybody can tell me the reason? Thanks very much....
However, for single supply case, (Vss=0), the output DC level is normally set to Vdd/2 for maximum swing, it seems the DC current to the load is quite large even no input signal is applied. For example, Vdd/2=1.5v, Rload=50Ω, then Iload=30mA even without signal input ?
What's the problem? Does it mean for drving a low load we always use dual supply?
Anybody can tell me the reason? Thanks very much....