| 摘要 |
A low voltage differential swing circuit includes a clamping circuit to prevent the output high voltage from exceeding a reference voltage. The low voltage differential swing circuit also includes a current source coupled to a control node and a current steering circuit coupled between the control node and first and second output nodes. The current source provides a constant drive current, and in response to first and second input signals, the current steering circuit generates first and second drive currents, wherein the first and second drive currents together form at the first and second output nodes a differential output signal. The clamping circuit comprises a operational amplifier and a shunting circuit. The operational amplifier senses the difference between a reference voltage and a voltage level at the control node, which voltage level varies in relation to the voltage level of the differential output signal. When the voltage level at the control node transcends the reference voltage value, the excess drive current, or overload current, is shunted away from the first and second output nodes by the shunting circuit. Thus, the overload current is prevented from reaching the first and second output nodes.
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