# US 2014/0191814 A1 · Oscillation control circuit for biasing ring oscillator by bandgap reference signal and related method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0191814 A1 - Document ID: US20140191814A1 - Status: Published application - Kind: A1 - Application number: 13/736,085 - Filed: 2013-01-08 - Published: 2014-07-10 - Earliest claimed: 2013-01-08 - Assignees: Elite Semiconductor Memory Technology Inc. - Applicants: Elite Semiconductor Memory Technology Inc. - Inventors: Ming-Sheng Tung - Web page: https://patentgrep.com/patent/US20140191814A1 ## CPC - H03K 3/0315: {Ring oscillators} - H03K 3/011: Modifications of generator to compensate for variations in physical values, e.g. voltage, temperature {(to maintain energy constant H03K3/015)} - H03B 5/04: Modifications of generator to compensate for variations in physical values, e.g. power supply, load, temperature - H03L 7/0995: {the oscillator comprising a ring oscillator} - 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) - 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 oscillation control circuit for a ring oscillator includes a bandgap reference circuit and an oscillation frequency control circuit. The bandgap reference circuit is arranged for generating a bandgap reference signal by mirroring a proportional-to-absolute-temperature current. The oscillation frequency control circuit is coupled to the bandgap reference circuit, and is arranged for biasing the ring oscillator according to the bandgap reference signal. When the ring oscillator has a plurality of stages, the oscillation frequency control circuit includes one current source and a plurality of current mirrors for biasing the plurality of stages of the ring oscillator, respectively. ## Claims ### Claim 1 An oscillation control circuit for a ring oscillator, comprising: a bandgap reference circuit, for generating a bandgap reference signal by mirroring a proportional-to-absolute-temperature current; and an oscillation frequency control circuit, coupled to the bandgap reference circuit, for biasing the ring oscillator according to the bandgap reference signal. ### Claim 2 (depends on 1) The oscillation control circuit of claim 1, wherein the bandgap reference circuit comprises: a first transistor, having a first connection node, a second connection node and a control node, the first connection node of the first transistor being coupled to a first reference voltage, and the second connection node of the first transistor being coupled to the control node of the first transistor; a resistor, having a first end and a second end, the first end of the resistor being coupled to the second connection node of the first transistor; and a second transistor, having a first connection node, a second connection node and a control node, the first connection node of the second transistor being coupled to the second end of the resistor, the second connection node of the second transistor being coupled to the second reference voltage, and the control node of the second transistor being coupled to a current source providing the proportional-to-absolute-temperature current. ### Claim 3 (depends on 1) The oscillation control circuit of claim 1, wherein the oscillation frequency control circuit comprises: a first transistor, having a first connection node, a second connection node and a control node, the first connection node of the first transistor being coupled to a first reference voltage, and the control node of the first transistor being coupled to the bandgap reference signal; and a second transistor, having a first connection node, a second connection node and a control node, the first connection node of the second transistor being coupled to the control node of the second transistor, and the second connection node of the second transistor being coupled to a second reference voltage. ### Claim 4 (depends on 3) The oscillation control circuit of claim 3, wherein the oscillation frequency control circuit further comprises at least one current mirror for biasing a corresponding stage of the ring oscillator, and the at least one current mirror comprises: a third transistor, having a first connection node, a second connection node and a control node, the first connection node of the third transistor being coupled to the first reference voltage, the second connection node of the third transistor being coupled to the corresponding stage of the ring oscillator, and the control node of the third transistor being coupled to the control node of the first transistor; and a fourth transistor, having a first connection node, a second connection node and a control node, the first connection node of the fourth transistor being coupled to the corresponding stage of the ring oscillator, the second connection node of the fourth transistor being coupled to the second reference voltage, and the control node of the fourth transistor being coupled to the control node of the second transistor. ### Claim 5 (depends on 1) The oscillation control circuit of claim 1, wherein the oscillation frequency control circuit comprises: a transistor, having a first connection node, a second connection node and a control node, the first connection node of the transistor being coupled to a first reference voltage, the second connection node of the transistor being coupled to a corresponding stage of the ring oscillator, and the control node of the transistor being coupled to the bandgap reference signal. ### Claim 6 An oscillation control method for a ring oscillator, comprising: generating a bandgap reference signal by mirroring a proportional-to-absolute-temperature current; and biasing the ring oscillator according to the bandgap reference signal. ### Claim 7 (depends on 6) The oscillation control method of claim 6, wherein the step of generating a bandgap reference signal comprises: generating a first current; generating a second current by mirroring the first current; and generating a third current by mirroring the second current, and generating the bandgap reference signal according to the third current. ### Claim 8 (depends on 6) The oscillation control method of claim 6, wherein the step of biasing the ring oscillator according to the bandgap reference signal comprises: providing a current according to the bandgap reference signal; and generating a plurality of operating currents corresponding to a plurality of stages of the ring oscillator by mirroring the current provided, respectively. ### Claim 9 (depends on 6) The oscillation control method of claim 6, wherein the step of biasing the ring oscillator according to the bandgap reference signal comprises: controlling a plurality of current sources which is coupled to the plurality of stages of the ring oscillator via the bandgap reference signal, respectively, to generate a plurality of operating currents to the plurality of stages of the ring oscillator.