Combined logic gate and latch
First Claim
1. A circuit comprising:
- a latch;
a logic gate having an output terminal coupled to an input terminal of the latch, wherein when input signals to the logic gate are selected constant voltages, the logic gate dissipates power while power through the logic gate is enabled;
a first switching circuit coupled to disable power through the logic gate when the latch operates in a latched mode and enable power through the logic gate when the latch operates in a flow-through mode; and
a second switching circuit coupled between the logic gate and the input terminal of the latch, wherein the second switching circuit connects the logic gate to the latch when the latch operates in the flow-through mode and disconnects the logic gate from the latch when the latch operates in the latched mode.
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Accused Products
Abstract
A circuit combines the functions of a logic gate and a latch to lower steady state power dissipation during gate operation. The circuit operates in two modes: a flow-through mode and a latched mode. In the flow-through mode, a gate portion which receives one or more digital input signals implements the complement of a desired Boolean logic function on the input signals and provides an internal signal. The gate portion may have a steady-state power dissipation while providing the internal signal. An inverter in a latch portion of the circuit inverts the internal signal to generate an output signal which represents the desired logical combination of the input signals. The inverter provides the output signal with a full-range CMOS voltage. In latched mode, the gate portion is disabled to stop the steady-state power dissipation while the latch portion of the circuit preserves the desired output signal.
21 Citations
12 Claims
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1. A circuit comprising:
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a latch; a logic gate having an output terminal coupled to an input terminal of the latch, wherein when input signals to the logic gate are selected constant voltages, the logic gate dissipates power while power through the logic gate is enabled; a first switching circuit coupled to disable power through the logic gate when the latch operates in a latched mode and enable power through the logic gate when the latch operates in a flow-through mode; and a second switching circuit coupled between the logic gate and the input terminal of the latch, wherein the second switching circuit connects the logic gate to the latch when the latch operates in the flow-through mode and disconnects the logic gate from the latch when the latch operates in the latched mode. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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Specification