Multichannel driver circuitry and operation

A multichannel driver apparatus for driving a plurality of transducers in different channels based on respective input signals, comprising:

• a plurality of output stages, each output stage comprising at least one driver output node for connection to a respective one of the plurality of transducers,
• wherein each output stage is configured such that the at least one driver output node can be modulated between selected switching voltages with a controlled duty cycle, and wherein each output stage is operable in a plurality of different modes of operation in which the switching voltages are different in the different modes;
• and
• wherein a first set of two or more of said plurality of output stages is configured to be operable to use a first voltage which is generated at a first voltage node as one of the switching voltages;
• and
• a controller configured to control the mode of operation and duty-cycle of each of the plurality of output stages based on a respective input signal, wherein the controller is configured to further control the mode of operation and/or duty-cycle of each of the output stages of the first set based on operation of the other output stages of the first set.

A driver apparatus for driving a transducer based on an input signal, comprising:

• a first output stage comprising at least one driver output node for connection to said transducer, and
• a controller for controlling the first output stage to modulate the at least one driver output node between selected switching voltages of a set of switching voltages with a controlled duty cycle, wherein the controller is configured to selectively operate the first output stage in a selected one of a plurality of different modes of operation in which the selected switching voltages are different in the different modes;
• wherein at least a first switching voltage of the set of switching voltages is generated by a first voltage generator;
• and
• wherein the controller is configured to identify first periods in which use of the first switching voltage should be avoided due to other load demands of the first voltage generator and is configured to control the mode of operation and/or duty-cycle of the first output stage to avoid using the first switching voltage as a selected switching voltage in said first periods.