METHOD AND APPARATUS FOR CLOCK GATING CLOCK TREES TO REDUCE POWER DISSIPATION

A clock gating circuit reduces the power dissipation in a digital circuit including at least one functional block by gating the clock signal at an input to a clock tree feeding the functional block. The clock gating circuit includes a logic gate that receives a clock signal and a clock disable signal generated by the functional block, and gates the clock signal at the input to the clock tree feeding the functional block. Further, a global signal generator is provided to transmit a global signal to each of the functional blocks to prevent the generation of clock disable signals, when necessary, such as during testing of chips.