Semiconductor integrated circuit and semiconductor physical quantity sensor device

Abstract

In aspects of the invention, an auxiliary memory circuit includes a shift register wherein a plurality of flip-flops are cascade-connected and a plurality of inversion circuits that invert and output outputs of each D flip-flop. A main memory circuit includes a switch, which acts in accordance with a signal from the auxiliary memory circuit, and an EPROM connected in series to the switch and driven by a writing voltage. A variable resistance circuit includes a switch, which acts in accordance with a signal from the auxiliary memory circuit, and a resistor connected in series to the switch. With aspects of the invention, it is possible for terminals of the writing voltage and a writing voltage to be commonized. Also, it is possible to provide a low-cost semiconductor physical quantity sensor device that can carry out electrical trimming with the voltage when writing into the EPROM kept constant.

1 . A semiconductor integrated circuit, comprising:
 a data input terminal that inputs serial digital data;   a ground terminal that supplies ground potential;   a power source terminal that supplies power source voltage;   an auxiliary memory circuit that temporarily stores trimming data input from the data input terminal;   a programmable read only main memory circuit that stores trimming data stored in the auxiliary memory circuit using an electrical rewrite action;   a writing terminal that inputs an external clock, or that supplies a first writing voltage, equal to or higher than the power source voltage, for writing data into the main memory circuit;   a variable resistance circuit that, based on the first writing voltage input from the writing terminal, generates a second writing voltage, which is equal to or higher than the power source voltage and wherein the first writing voltage is divided by resistance of the main memory circuit, for writing data into the main memory circuit, and supplies the second writing voltage to the main memory circuit; and   a signal distinguishing means that determines whether voltage applied to the writing terminal is an external clock, or whether it is the first writing voltage, supplies the external clock to the auxiliary memory circuit, and supplies the first writing voltage to the main memory circuit, wherein   the auxiliary memory circuit is configured of a shift register wherein a plurality of flip-flops are cascade connected,   the main memory circuit includes a first series circuit, corresponding to each flip-flop, formed of a first switch and an EPROM connected in series to the first switch and driven by the first writing voltage,   the variable resistance circuit includes a second series circuit, corresponding to each flip-flop, formed of a second switch and a resistor connected in series to the second switch,   a plurality of the first series circuits and a plurality of the second series circuits are connected in series, and   when the first writing voltage is applied, the number of the second switches turned on is the same as the number of the first switches turned on.   
     
     
         2 . The semiconductor integrated circuit according to  claim 1 , wherein
 the first switch and second switch are formed of p-channel MOSFETs, and   when the first writing voltage is applied, the turning on and off of the first switch of the first series circuit corresponding to a certain flip-flop is controlled based on the output of the flip-flop, and the turning on and off of the second switch of the second series circuit corresponding to a certain flip-flop is controlled based on the output of the flip-flop.   
     
     
         3 . A semiconductor physical quantity sensor device, comprising:
 a sensor element that generates an electrical signal in accordance with a detected physical quantity;   an output terminal that outputs the electrical signal generated by the sensor element to the exterior;   a data input terminal that inputs serial digital data, which form trimming data for regulating the output characteristics of the sensor element;   a ground terminal that supplies ground potential;   a power source terminal that supplies power source voltage;   an auxiliary memory circuit that temporarily stores trimming data input from the data input terminal;   a programmable read only main memory circuit that stores trimming data stored in the auxiliary memory circuit using an electrical rewrite action;   a writing terminal that inputs an external clock, or that supplies a first writing voltage, equal to or higher than the power source voltage, for writing data into the main memory circuit;   a variable resistance circuit that, based on the first writing voltage input from the writing terminal, generates a second writing voltage, which is equal to or higher than the power source voltage and wherein the first writing voltage is divided by resistance of the main memory circuit, for writing data into the main memory circuit, and supplies the second writing voltage to the main memory circuit;   an action selection circuit that controls an action of the auxiliary memory circuit and main memory circuit based on one portion of digital data stored in the auxiliary memory circuit;   a signal distinguishing means that determines whether voltage applied to the writing terminal is an external clock, or whether it is the first writing voltage, supplies the external clock to the auxiliary memory circuit, and supplies the first writing voltage to the main memory circuit; and   a regulation circuit that regulates the output characteristics of the sensor element based on trimming data stored in the auxiliary memory circuit or trimming data stored in the main memory circuit, wherein   the auxiliary memory circuit is configured of a shift register wherein a plurality of flip-flops are cascade connected,   the main memory circuit includes a first series circuit, corresponding to each flip-flop, formed of a first switch and an EPROM connected in series to the first switch and driven by the first writing voltage,   the variable resistance circuit includes a second series circuit, corresponding to each flip-flop, formed of a second switch and a resistor connected in series to the second switch,   a plurality of the first series circuits and a plurality of the second series circuits are connected in series, and   when the first writing voltage is applied, the number of the second switches turned on is the same as the number of the first switches turned on.   
     
     
         4 . The semiconductor physical quantity sensor device according to  claim 3 , wherein
 the first switch and second switch are formed of p-channel MOSFETs, and   when the first writing voltage is applied, the turning on and off of the first switch of the first series circuit corresponding to a certain flip-flop is controlled based on the output of the flip-flop, and the turning on and off of the second switch of the second series circuit corresponding to a certain flip-flop is controlled based on the output of the flip-flop.   
     
     
         5 . The semiconductor physical quantity sensor device according to  claim 3 , the semiconductor physical quantity sensor device consisting of only an active element and a passive element, formed on the same semiconductor chip, manufactured by a CMOS manufacturing process. 
     
     
         6 . The semiconductor physical quantity sensor device according to  claim 4 , the semiconductor physical quantity sensor device consisting of only an active element and a passive element, formed on the same semiconductor chip, manufactured by a CMOS manufacturing process.