Semiconductor apparatus
View Patent ↗Disclosed is a semiconductor apparatus adapted to reduce the inflow of current from an external input terminal in a power saving mode. A mode decision circuit 11 outputs to an interruption circuit 10 and a floating prohibiting circuit 15 a mode signal indicating whether operation of the semiconductor apparatus is power saving mode or regular operating mode. When the mode signal indicates the power saving mode, the interruption circuit 10 is rendered non-conductive to disconnect an external input terminal 13 on one hand and an input capacitance adjustment capacitor 12 and an initial stage input circuit 14 on the other hand from each other. The floating prohibiting circuit 15 also sets the voltage at an input end of the initial stage input circuit 14 at a preset voltage level. When the mode signal indicates the regular operating mode, the interruption circuit 10 is rendered conductive, such that the input capacitance adjustment capacitor 12 and the initial stage input circuit 14 are connected via a static charge breakdown prohibiting resistor device 21 to the external input terminal 13 to transmit an input signal of the external input terminal 13 to the initial stage input circuit 14.
1. A semiconductor apparatus comprising:
an external input terminal;
an input capacitance adjustment capacitor that adds a capacitance to said external input terminal;
a mode decision circuit that outputs a mode signal indicating whether the operation of the semiconductor apparatus is a power saving mode or a regular operation mode;
an interruption circuit interposed between said external input terminal and said input capacitance adjustment capacitor, said interruption circuit being supplied with said mode signal and rendered non-conductive and conductive when said mode signal indicates the power saving mode and the regular operation mode, respectively; and
an initial stage input circuit connected to said external input terminal at least in case where the semiconductor apparatus operation is at the regular operation mode.
2. The semiconductor apparatus as defined in claim 1 , wherein
said external input terminal is connected to one end of said interruption circuit; said input capacitance adjustment capacitor and said initial stage input circuit are connected to the other end of said interruption circuit;
said external input terminal and said input capacitance adjustment capacitor on one hand and said initial stage input circuit on the other are (i) isolated from each other, or (ii) rendered conductive, by said interruption circuit in case where said mode signal indicates (i) the power saving mode, or (ii) the regular operating mode, respectively.
3. The semiconductor apparatus as defined in claim 2 further comprising:
a floating prohibiting circuit that sets the voltage of an input end of said initial stage input circuit at a preset voltage level in case the power saving mode prevails.
4. The semiconductor apparatus as defined in claim 1 further comprising:
a static charge breakdown prohibiting resistor device interposed between one end of said interruption circuit and said external input terminal.
5. The semiconductor apparatus as defined in claim 1 , wherein
said external input terminal and said initial stage input circuit are connected to one end of said interruption circuit; said input capacitance adjustment capacitor is connected to the other end of said interruption circuit;
said external input terminal and said input capacitance adjustment capacitor are (i) isolated from each other, or (ii) rendered conductive, by said interruption circuit in case where said mode signal indicates (i) said power saving mode, or (ii) said regular operating mode, respectively.
6. The semiconductor apparatus as defined in claim 1 wherein
said external input terminal, to which said interruption circuit is connected, is an input terminal different from the input terminal supplied with the information needed for the operation of restoration from said power saving mode to said regular operating mode.
7. The semiconductor apparatus as defined in claim 1 wherein
said interruption circuit in a conducting state has a resistance value not larger than 1 kΩ.
8. The semiconductor apparatus as defined in claim 1 wherein
said interruption circuit is a switching circuit formed by a MOS transistor and wherein said mode signal is sent to a control terminal of said MOS transistor.
9. The semiconductor apparatus as defined in claim 7 wherein
said interruption circuit is a switching circuit formed by a MOS transistor and wherein said mode signal is sent to a control terminal of said MOS transistor.
10. The semiconductor apparatus as defined in claim 1 wherein
said interruption circuit is a switching circuit formed by a transfer gate and wherein said mode signal is supplied to a control terminal of said transfer gate.
11. The semiconductor apparatus as defined in claim 7 wherein
said interruption circuit is a switching circuit formed by a transfer gate and wherein said mode signal is supplied to a control terminal of said transfer gate.