Power saving circuit and method for driving an active matrix display

A power-saving circuit for driving I even electrodes and J odd electrodes of an active matrix display, where I and J are positive integers, the circuit including:

• I even voltage drivers, each said even voltage driver adapted to receive even pixel data and being coupled to a corresponding even electrode;
• J odd voltage drivers, each said odd voltage driver adapted to receive odd pixel data and being coupled to a corresponding odd electrode;
• I even switches, each said even switch coupling the corresponding even electrode to a first reservoir line;
• J odd switches, each said odd switch coupling the corresponding odd electrode to a second reservoir line;
• I even decision circuits adapted to receive the even pixel data for controlling on an individual basis the I even switches such that the I even electrodes may be connected on an individual basis to the even reservoir depending on the even pixel data;
• J odd decision circuits adapted to receive the even pixel data for controlling on an individual basis the J odd switches such that the J odd electrodes may be connected on an individual basis to the odd reservoir depending on the odd pixel data;
• a neutralizer switch coupling the first reservoir line to the second reservoir line under control of a neutralizer signal such that the even and second reservoir lines are electrically connected together when the neutralizer signal is asserted, and such that the even and second reservoir lines are electrically isolated from each other when the neutralizer signal is de-asserted;
• a positive storage element for storing charge at a positive voltage level relative to a midpoint voltage level;
• a negative storage element for storing charge at a negative voltage level relative to the midpoint voltage level;
• a matrix switch including a straight mode and a cross mode;
• where the matrix switch in the straight mode electrically connects the first reservoir line to the positive storage element and the second reservoir line to the negative storage element;
• and
• where the matrix switch in the cross mode electrically connects the first reservoir line to the negative storage element and the second reservoir line to the positive storage element.

A power-saving circuit for driving column electrodes of an active matrix display in a scheme involving row inversion and back plane switching, the circuit including:

• a back plane node;
• a high voltage source;
• a high enable switch for electrically connecting the high voltage source to the back plane node when a high enable signal is asserted and for electrically isolating the high voltage source from the back plane node when a high enable signal is de-asserted;
• a low voltage source;
• a low enable switch for electrically connecting the low voltage source to the back plane node when a low enable signal is asserted and for electrically isolating the low voltage source from the back plane node when a low enable signal is de-asserted;
• a first storage element;
• a first storage switch for electrically connecting the first storage element to the back plane node when a first storage signal is asserted and for electrically isolating the first storage element from the back plane node when a first storage signal is de-asserted;
• a second storage element;
• and
• a second storage switch for electrically connecting the second storage element to the back plane node when a second storage signal is asserted and for electrically isolating the second storage element from the back plane node when a second storage signal is de-asserted.

A power-saving circuit for driving N column electrodes of an active matrix display, where N is a positive integer, the circuit including:

• N voltage drivers, each said voltage driver being coupled to a corresponding column electrode;
• N−1 switches, each said switch coupling the corresponding column electrode to a next corresponding column electrode;
• and
• a neutralizer enable line for controlling the N−1 switches such that the N−1 switches electrically connect the N column electrodes when the neutralizer enable line asserts a signal, and such that the N−1 switches electrically isolate the N column electrodes when the neutralizer enable line de-asserts the signal.

A power-saving method for driving electrodes coupled to cells of an active matrix display, the method including:

• driving a first set of the electrodes to a first positive voltage level relative to a midpoint voltage level and a second set of electrodes to a first negative voltage level relative to the midpoint voltage level;
• electrically connecting the first set of electrodes to a first reservoir line and the second set of electrodes to a second reservoir line;
• electrically connecting the first reservoir line to a first storage device and the second reservoir line to a second storage device;
• electrically disconnecting the first reservoir line from the first storage device and the second reservoir line from the second storage device;
• electrically connecting the first reservoir line to the second reservoir line;
• electrically disconnecting the first reservoir line from the second reservoir line;
• electrically connecting the first reservoir line to the second storage device and the second reservoir line to the first storage device;
• electrically disconnecting the first reservoir line from the second storage device and the second reservoir line from the first storage device;
• and
• electrically disconnecting the first set of electrodes from the first reservoir line and the second set of electrodes from the second reservoir line.