Intermediate Combinational Circuits 13 components
Full Subtractor
Subtracts two bits and an incoming borrow, producing a Difference and an outgoing Borrow. Chains to build multi-bit subtractors.
What You'll Learn
- Combine two bits and a borrow into Difference and Borrow-out
- Cascade full subtractors for multi-bit subtraction
- Read a 3-input borrow expression
How It Works
It subtracts B and an incoming Borrow from A. Difference = A XOR B XOR Bin. Borrow-out is high whenever the running subtraction needs to borrow, expressed as A'·B + A'·Bin + B·Bin. Chain several to subtract multi-bit numbers.
Components Used
Real-World Applications
Multi-bit subtractors, adder/subtractor units, and the arithmetic core of processors.