Abstract: A printed circuit board having a first switching device (S1 or S2), a second switching device (S3 or S4), a third switching device (S5 or S6), and a common source node (26 or 166) that are each mounted to a surface of the printed circuit board (50 or 150). The printed circuit board further includes at least a first set of conductive paths in a first layer, a second set of conductive paths in a second layer, and a plurality of vias that connects the first layer to the second layer. The first set of conductive paths provides electrical conductivity between the common source node, the first switching device, the second switching device, and third switching device. The second set of conductive paths in the second layer provides electrical conductivity between the common source node, the first switching device, and the third switching device.

Abstract: A low power consumption switch interface circuit (100) includes a current source (109) for providing switch current (144) having a magnitude dependent on a state of a current range signal (135). An input terminal (142) is provided to conduct the switch current (144) to an external switch (102). A circuit (101, 103, 119) for detecting a signal (141) present at the input terminal (142) provides a measured pulse (127) when the signal (141) is detected. A current range selector (129), coupled to the current source (109), outputs a first state of the current range signal (135) while the measured pulse (127) is outputted from the circuit (101, 103, 119), and a second state of the current range signal (135) while the measured pulse (127) is not outputted from the circuit (101, 103, 119).

Abstract: A meter drive inhibit circuit is provided whereby an erroneous jump of the meter pointer upon system power-up or subsequent microcomputer reset operation is inhibited. A pulse generator is utilized to produce output pulses relating to the rate of rotation of a drive shaft in a typical tachometer application. Such output pulses are provided to a meter drive circuit which in turn provides an output to an electromechanical meter. Such electromechanical meter will display an output related to the time average value of pulses input to the meter drive circuit. An inhibit circuit stage is connected to the meter drive. A microcomputer is utilized to sense the power-up condition of the meter circuit and activate the inhibit stage. When activated, the inhibit stage will prohibit the meter drive from providing an output to the meter and thereby prevent the erroneous jump of the meter pointer upon system power-up.