A system for backlighting a display uses an open or closed loop and small components that are well suited to high-frequency applications. The system includes multiple LED strings, a high-voltage source, and a low-voltage regulator that has a polarity opposite to that of the high-voltage source. The high-voltage source and the low-voltage regulator provide voltage differences across the LED strings to illuminate them. In one embodiment, the high-voltage source is about 200 VDC, and the low-voltage regulator produces voltages between −2 VDC and −30 VDC. Many types of displays, such as those used on LCD televisions and LCD personal computers, can be backlit in accordance with the embodiments.