High-reliability low-loss power switch and driver IC

A power switch controller comprising:

• a condition detector with one or more sense inputs and a condition result output;
• a zero crossing detector with a zero input, and a zero crossing indicator output;
• a retimer with a condition result input coupled with the condition result output to receive a detected conditions signal, a zero crossing input coupled with the zero crossing indicator output, and one or more retimed signal outputs;
• and
• a driver with an input coupled with the one or more retimed signal outputs, and one or more coil outputs;
• wherein:
• the detected conditions signal includes a must-make value and a must-break value;
• the one or more sense inputs, the zero input and the one or more coil outputs are coupled with external terminals of the power switch controller;
• the condition detector includes a threshold detector and/or a window detector;
• the condition detector generates the detected conditions signal in response to a sense signal on the sense input by comparing a sense signal value with a threshold in the threshold detector and/or by comparing the sense signal value with a window in the window detector;
• the zero crossing detector is configured to detect times of zero transitions in an AC power signal;
• the retimer is configured to output a retimed signal in response to a change in the detected conditions signal by waiting for a time of a zero transition in the AC power signal and outputting a retimed must-make value after a first delay time after the zero transition in the AC power signal or outputting a retimed must-break value after a second delay time after the zero transition in the AC power signal;
• the driver is configured to output a first shaped pulse on one of the one or more coil outputs in response to a retimed must-make value and to output a second shaped pulse on one of the one or more coil outputs in response to a retimed must-break value;
• the first shaped pulse and the second shaped pulse each have a duration shorter than 20 milliseconds;
• and
• the first shaped pulse begins at least 50 milliseconds after a prior second shaped pulse has ended.

An AC switch system, comprising:

• a latching relay coupled between a power line and a load;
• a power switch controller configured to drive the latching relay and coupled with a latching relay coil via at least one coil output;
• and
• a zero crossing detection resistor coupled between the power line and a power switch controller zero input;
• a sense input of the power switch controller, sensing one or more predetermined conditions that cause the power switch controller to activate the latching relay by applying a first shaped pulse to a first coil terminal of the latching relay, and/or to deactivate the latching relay by applying a second shaped pulse to a second coil terminal of the latching relay, wherein:
• the first shaped pulse and the second shaped pulse each have a duration shorter than 20 milliseconds;
• the first shaped pulse and the second shaped pulse each have a maximum amplitude of at least 110% of a maximum sustained coil voltage;
• and
• the first shaped pulse begins at least 50 milliseconds after a prior second shaped pulse has ended.