# US 7,746,143 B2 · Clock generating circuit and semiconductor device provided with clock generating circuit > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,746,143 B2 - Document ID: US7746143B2 - Status: Granted - Kind: B2 - Application number: 11/984,463 - Filed: 2007-11-19 - Published: 2008-10-23 - Granted: 2010-06-29 - Earliest claimed: 2006-11-30 - Assignees: Semiconductor Energy Laboratory Co., Ltd. - Inventors: Masami Endo - Web page: https://patentgrep.com/patent/US7746143B2 ## CPC - H03K 3/011: Modifications of generator to compensate for variations in physical values, e.g. voltage, temperature {(to maintain energy constant H03K3/015)} - G06K 19/0705: {the battery being connected to a power saving arrangement} - G06K 19/0723: {the record carrier comprising an arrangement for non-contact communication, e.g. wireless communication circuits on transponder cards, non-contact smart cards or RFIDs} - H03B 5/30: with frequency-determining element being electromechanical resonator - H03K 3/354: Astable circuits - H03L 1/00: Stabilisation of generator output against variations of physical values, e.g. power supply - H03L 7/00: Automatic control of frequency or phase; Synchronisation - H03K: PULSE TECHNIQUE (measuring pulse characteristics G01R; modulating sinusoidal oscillations with pulses H03C; transmission of digital information H04L; discriminator circuits detecting phase difference between two signals by counting or integrating cycles of oscillation H03D3/04; automatic control, starting, synchronisation or stabilisation of generators of electronic oscillations or pulses where the type of generator is irrelevant or unspecified H03L; coding, decoding or code conversion, in general H03M) - G06K: GRAPHICAL DATA READING (image or video recognition or understanding G06V); PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS - H03B: GENERATION OF OSCILLATIONS, DIRECTLY OR BY FREQUENCY-CHANGING, BY CIRCUITS EMPLOYING ACTIVE ELEMENTS WHICH OPERATE IN A NON-SWITCHING MANNER; GENERATION OF NOISE BY SUCH CIRCUITS (generators adapted for electrophonic musical instruments G10H; masers or lasers H01S; generation of oscillations in plasma H05H) - H03L: AUTOMATIC CONTROL, STARTING, SYNCHRONISATION OR STABILISATION OF GENERATORS OF ELECTRONIC OSCILLATIONS OR PULSES (generation of oscillations H03B) ## Abstract An object is to provide a clock generating circuit that can suppress variation of an oscillation frequency from the clock generating circuit, which is due to a change in the output voltage according to a discharging characteristic of the battery, and effectively utilize the remaining power of the battery. A structure includes an output voltage detecting circuit for detecting an output voltage from a battery; a frequency-division number determining circuit for determining the number of frequency-division by a value of the output voltage detected by the output voltage detecting circuit; an oscillation circuit for outputting a reference clock signal depending on the output voltage; a counter circuit for counting a number of waves of the reference clock signal that depends on the number of frequency-division; and a frequency-dividing circuit that frequency-divides the reference clock signal depending on the number of waves counted by the counter circuit. ## Claims ### Claim 1 A clock generating circuit comprising: an output voltage detecting circuit for detecting an output voltage from a battery; a frequency-division number determining circuit for determining the number of frequency-division by a value of the output voltage detected by the output voltage detecting circuit; an oscillation circuit for outputting a reference clock signal depending on the output voltage; a counter circuit for counting a number of waves of the reference clock signal; and a frequency-dividing circuit that frequency-divides the reference clock signal wherein the counter circuit outputs a signal for performing a frequency-division with the number of frequency-division determined by the frequency-division number determining circuit when the counted number of waves reaches a number of waves corresponding to the number of frequency-division after the counter circuit outputs a signal for performing a frequency-division once. ### Claim 2 (depends on 1) The clock generating circuit according to claim 1, wherein the battery is a primary battery or a secondary battery. ### Claim 3 (depends on 1) The clock generating circuit according to claim 1, wherein the oscillation circuit is a ring oscillator or a crystal oscillator. ### Claim 4 A clock generating circuit comprising: an output voltage detecting circuit for detecting an output voltage from a battery; a frequency-division number determining circuit for determining the number of frequency-division by a value of the output voltage detected by the output voltage detecting circuit; an oscillation circuit for outputting a reference clock signal depending on the output voltage; a counter circuit for counting a number of waves of the reference clock signal; and a frequency-dividing circuit that outputs a signal, which is the reference clock signal that is frequency-divided, as a clock signal, to a logic circuit, wherein the counter circuit outputs a signal for performing a frequency-division with the number of frequency-division determined by the frequency-division number determining circuit when the counted number of waves reaches a number of waves corresponding to the number of frequency-division after the counter circuit outputs a signal for performing a frequency-division once. ### Claim 5 (depends on 4) The clock generating circuit according to claim 4, wherein the battery is a primary battery or a secondary battery. ### Claim 6 (depends on 4) The clock generating circuit according to claim 4, wherein the oscillation circuit is a ring oscillator or a crystal oscillator. ### Claim 7 A semiconductor device equipped with an antenna and performs transmission and reception of a signal by wireless communication with a reader/writer comprising: a clock generating circuit; a logic circuit; and a battery, wherein the clock generating circuit includes: an output voltage detecting circuit for detecting an output voltage from a battery; a frequency-division number determining circuit for determining the number of frequency-division by a value of the output voltage detected by the output voltage detecting circuit; an oscillation circuit for outputting a reference clock signal depending on the output voltage; a counter circuit for counting a number of waves of the reference clock signal; and a frequency-dividing circuit that frequency-divides the reference clock signal, wherein the counter circuit outputs a signal for performing a frequency-division with the number of frequency-division determined by the frequency-division number determining circuit when the counted number of waves reaches a number of waves corresponding to the number of frequency-division after the counter circuit outputs a signal for performing a frequency-division once. ### Claim 8 (depends on 7) The semiconductor device according to claim 7, wherein the battery is a primary battery or a secondary battery. ### Claim 9 (depends on 7) The semiconductor device according to claim 7, wherein the oscillation circuit is a ring oscillator or a crystal oscillator. ### Claim 10 A semiconductor device equipped with an antenna and performs transmission and reception of a signal by wireless communication with a reader/writer comprising: a clock generating circuit; a logic circuit; and a battery, wherein the clock generating circuit includes: an output voltage detecting circuit for detecting an output voltage from a battery; a frequency-division number determining circuit for determining the number of frequency-division by a value of the output voltage detected by the output voltage detecting circuit; an oscillation circuit for outputting a reference clock signal depending on the output voltage; a counter circuit for counting a number of waves of the reference clock signal; and a frequency-dividing circuit that outputs a signal, which is the reference clock signal that is frequency-divided, as a clock signal, to a logic circuit, wherein the counter circuit outputs a signal for performing a frequency-division with the number of frequency-division determined by the frequency-division number determining circuit when the counted number of waves reaches a number of waves corresponding to the number of frequency-division after the counter circuit outputs a signal for performing a frequency-division once. ### Claim 11 (depends on 10) The semiconductor device according to claim 10, wherein the battery is a primary battery or a secondary battery. ### Claim 12 (depends on 10) The semiconductor device according to claim 10, wherein the oscillation circuit is a ring oscillator or a crystal oscillator.