Low power pulse width modulation by controlling bits order

A head-mounted display (HMD), comprising:

• a display panel;
• a panel driver connected to the display panel;
• a pulse-width modulation (PWM) driver connected to the display panel;
• and
• a controller configured to:
• associate each bit of a grayscale value for a sub-pixel of the display panel with a pulse of a PWM signal, the PWM signal including a sequence of pulses;
• generate a modified digital word including a modified bit sequence by modifying a bit sequence of the grayscale value, the modified bit sequence including a fewer number of transitions from a first voltage level to a second voltage level higher than the first voltage level as defined from a least significant bit to a most significant bit than the bit sequence of the grayscale value, the modified bit sequence including a same number of bits as the bit sequence of the grayscale value;
• generate a modified PWM signal including a modified sequence of pulses by ordering the pulses of the PWM signal according to the modified bit sequence of the modified digital word and the associations between each bit of the grayscale value and each pulse of the sequence of pulses of the PWM signal;
• provide the modified digital word to the display panel via the panel driver;
• and
• provide the modified PWM signal to the display panel via the PWM driver.

A method for controlling an electronic display, comprising:

• associating each bit of a grayscale value for a sub-pixel of a display panel of the electronic display with a pulse of a pulse-width modulation (PWM) signal, the PWM signal including a sequence of pulses;
• generating a modified digital word including a modified bit sequence by modifying a bit sequence of the grayscale value, the modified bit sequence including a fewer number of transitions from a first voltage level to a second voltage level higher than the first voltage level as defined from a least significant bit to a most significant bit than the bit sequence of the grayscale value, the modified bit sequence including a same number of bits as the bit sequence of the grayscale value;
• generating a modified PWM signal including a modified sequence of pulses by ordering the pulses of the PWM signal according to the modified bit sequence of the modified digital word and the associations between each bit of the grayscale value and each pulse of the sequence of pulses of the PWM signal;
• providing the modified digital word to the display panel via a panel driver;
• and
• providing the modified PWM signal to the display panel via a PWM driver.