The LM3914N-1 is a Monolithic Integrated Circuit senses analogue voltage levels and drives 10 LEDs, providing a linear analogue display. A single pin changes the display from a moving dot to a bar graph. Current drive to LEDs is regulated and programmable, eliminating need for resistors. This feature is one that allows operation of the whole system from less than 3V. It contains its own adjustable reference and accurate 10-step voltage divider.
The low-bias-current input buffer accepts signals down to ground or V-, yet needs no protection against inputs of 35V above or below ground. The buffer drives 10 individual comparators referenced to the precision divider. Indication non-linearity can thus be held typically to 1/2%, even over a wide temperature range. Versatility was designed into the LM3914 so that controller, visual alarm and expanded scale functions are easily added on to the display system. The circuit can drive LEDs of many colours or low-current incandescent lamps.
- Drives LEDs, LCDs or vacuum fluorescents
- Bar or dot display mode externally selectable by user
- Expandable to displays of 100 steps
- Operates with single supply of less than 3V
- Inputs operate down to ground
- Output current programmable from 2 to 30mA
- No multiplex switching or interaction between outputs
- Input withstands ±35V without damage or false outputs
- LED driver outputs are current regulated, open-collectors
- Outputs can interface with TTL or CMOS logic
- Internal 10-step divider is floating and can be referenced to a wide range of voltages