BCDto7seg

BCDto7seg (BCD to 7-segment) refers to a class of digital circuits that convert a binary-coded decimal input into the seven-segment control signals needed to drive a seven-segment display. The input is typically a 4-bit BCD value representing decimal digits 0 through 9. The circuit maps these values to the seven segment lines (labeled a through g) so that the corresponding numeral is shown on the display.

Most implementations are combinational decoders or decoders/drivers. They may also provide a decimal point output and support either common-cathode or common-anode displays, depending on the output polarity. In common-cathode configurations, a high output lights a segment; in common-anode configurations, a low output lights a segment. Many ICs implement the mapping via a truth table or a ROM lookup and may include optional features such as a latch, blanking input, ripple-blanking input, and a lamp-test function.

BCDto7seg devices are commonly integrated as stand-alone decoder/driver ICs or as parts of microcontroller peripherals. They are widely used in devices that need human-readable numeric output, including digital clocks, calculators, measurement instruments, meters, and embedded control panels. When designing a circuit, it is important to consider whether the display is common-cathode or common-anode, the required voltage levels, and whether only digits 0–9 should be displayed or whether additional symbols are needed for invalid inputs.

Common examples include parts from the 4511 family (BCD-to-7-segment for common-cathode displays) and the 7447 family (BCD-to-7-segment for common-anode displays), though exact behavior varies by manufacturer.