# US 5,703,475 A · Reference voltage generator with fast start-up and low stand-by power > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,703,475 A - Document ID: US5703475A - Status: Granted - Kind: A - Application number: 08/671,145 - Filed: 1996-06-24 - Granted: 1997-12-30 - Earliest claimed: 1995-06-24 - Assignees: Samsung Electronics Co., Ltd. - Inventors: Kyu-Chan Lee; Jai-Hoon Sim - Web page: https://patentgrep.com/patent/US5703475A ## CPC - G05F 3/242: {with compensation for device parameters, e.g. channel width modulation, threshold voltage, processing, or external variations, e.g. temperature, loading, supply voltage} - G05F: SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES ## Abstract A reference voltage generator includes a pull-up stage which pulls a reference voltage signal rapidly up toward 1/2Vcc at power-up. The pull-up stage is controlled by a controller which has a comparator and control voltage generator which are disabled after the pull-up operation is terminated so as to reduce stand-by current consumption. The controller includes a pair of NAND gates cross connected as an RS flip-flop to turn on the pull-up stage at power up. A boost signal allows the flip-flop to enable the comparator and control voltage generator after the power supply has stabilized. When the reference voltage signal reaches 1/2Vcc, the comparator sets the flip flop which turns off the pull-up stage and disables the comparator and control voltage generator. ## Claims ### Claim 1 A reference voltage generator comprising: a reference stage which generates a reference voltage signal; a controller coupled to the reference stage to receive the reference voltage signal, the controller generating a control signal responsive to the reference voltage signal; and a pull-up stage coupled to the controller to receive the control signal and coupled to the reference stage to pull up the reference voltage signal responsive to the control signal, the pull-up stage being capable of being switched off during normal operation; wherein the controller switches the pull-up stage off when the reference signal reaches a predetermined voltage. ### Claim 2 (depends on 1) A reference voltage generator according to claim 1 wherein the controller switches the pull-up stage on when power is applied to the reference voltage generator. ### Claim 3 (depends on 1) A reference voltage generator according to claim 1 wherein the controller includes a control voltage generator which generates a control voltage signal and a comparator coupled to the control voltage generator, the comparator generating an output signal responsive to the difference between the reference voltage signal and the control voltage signal. ### Claim 4 A reference voltage generator 3 wherein the comprising: a reference stage which generates a reference voltage signal: a controller coupled to the reference stage to receive the reference voltage signal, the controller generating a control signal responsive to the reference voltage signal; and a pull-up stage coupled to the controller to receive the control signal and coupled to the reference stage to pull up the reference voltage signal responsive to the control signal: wherein the controller includes: a control voltage generator which generates a control voltage signal: a comparator coupled to the control voltage generator the comparator generating an output signal responsive to the difference between the reference voltage signal and the control voltage signal: a latch coupled to the comparator for latching the output signal from the comparator, thereby generating a level detection signal; and a flip-flop coupled to the latch, the flip-flop generating the control signal responsive to the level detection signal. ### Claim 5 A reference voltage generator comprising: a reference stage which generates a reference voltage signal; a controller coupled to the reference stage to receive the reference voltage signal, the controller generating a control signal responsive to the reference voltage signal: and a pull-up stage coupled to the controller to receive the control signal and coupled to the reference stage to pull up the reference voltage signal responsive to the control signal; wherein the controller includes: a control voltage generator which generates a control voltage signal; a comparator coupled to the control voltage generator the comparator generating an output signal responsive to the difference between the reference voltage signal and the control voltage signal; and a flip-flop which disables the comparator and control voltage generator responsive to the output signal from the comparator. ### Claim 6 (depends on 5) A reference voltage generator according to claim 5 wherein the flip-flop enables the comparator and control voltage generator responsive to a boost signal. ### Claim 7 (depends on 1) A reference voltage generator according to claim 1 further including a first power supply node, a second power supply node, a reference node, and a control node, the reference stage generating the reference voltage signal at the reference node, the controller generating the control signal at the control node. ### Claim 8 A reference voltage generator 7 comprising: a reference stage which generates a reference voltage signal: a controller coupled to the reference stage to receive the reference voltage signal the controller generating a control signal responsive to the reference voltage signal: a pull-up stage coupled to the controller to receive the control signal and coupled to the reference stage to pull up the reference voltage signal responsive to the control signal: a first power supply node: a second power supply node; a reference node: and wherein the reference stage generates the reference voltage signal at the reference node, and the controller generates the control signal at the control node, and wherein the pull-up stage includes a transistor having a source coupled to the first power supply node, a drain coupled to the reference node, and a gate coupled to the control node, whereby the transistor pulls up the reference voltage signal responsive to the control signal at the control node. ### Claim 9 A reference voltage generator 7 comprising: a reference stage which generates a reference voltage signal; a controller coupled to the reference stage to receive the reference voltage signal, the controller generating a control signal responsive to the reference voltage signal; a pull-up stage coupled to the controller to receive the control signal and coupled to the reference stage to pull up the reference voltage signal responsive to the control signal; a first power supply node; a second power supply node: a reference node: and a control node: wherein the reference stage generates the reference voltage signal at the reference node, and the controller generates the control signal at the control node; and wherein the controller includes a control voltage generator including a first transistor having a source coupled to the first power supply node, a drain coupled to a control voltage node, and a gate coupled to the second power supply node, and a second transistor having a source coupled to the second power supply node, a drain coupled to the control voltage node, and a gate coupled to the first power supply node. ### Claim 10 (depends on 9) A reference voltage generator according to claim 9 wherein the controller further includes a comparator having a first input terminal coupled to the reference node, a second input terminal coupled to the control voltage node, and an output terminal coupled to the control node. ### Claim 11 (depends on 10) A reference voltage generator according to claim 10 wherein the controller further includes a latch including a fast inverter having an input terminal coupled to the output terminal of the comparator and an output terminal coupled to a level detection node, and a second inverter having an output terminal coupled to the input terminal of the first inverter and an output terminal coupled to the input terminal of the first inverter. ### Claim 12 (depends on 11) A reference voltage generator according to claim 11 wherein the controller further includes a flip-flop including a first NAND gate having a first input terminal coupled to the level detection node, a second input terminal coupled to an output terminal of a second NAND gate, and an output terminal coupled to the control node, the second NAND gate having a first input terminal coupled to a boost voltage node and a second input terminal coupled to the control node. ### Claim 13 (depends on 12) A reference voltage generator according to claim 12 wherein the comparator has a sink current terminal and the controller further includes a fast switching transistor having a source coupled to the second power supply node, a drain coupled to the sink current terminal, and a gate coupled to the output terminal of the second NAND gate, and a second switching transistor having a source coupled to the second power supply node, a drain coupled to the source of the second transistor of the control voltage generator, and a gate coupled to the output terminal of the second NAND gate. ### Claim 14 (depends on 12) A reference voltage generator according to claim 12 further including a boost voltage circuit including: a first transistor having a source coupled to the first power supply node, a drain coupled to the second power supply node through a resistor, and a gate coupled to the second power supply node through a capacitor; a second transistor having a drain coupled to the fast power supply node, a source coupled to the gate of the fast transistor, and a gate coupled to the gate of the first transistor; a first inverter having an input terminal coupled to the source of the second transistor; and a second inverter having an input terminal coupled to the output terminal of the first inverter and an output terminal coupled to the boost voltage node. ### Claim 15 A reference voltage generator comprising: means for generating a reference voltage signal; means for generating a control signal responsive to the reference voltage signal; and means for pulling up the reference voltage signal responsive to the control signal, said means being capable of being switched off during normal operation: wherein the means for generating a control signal switches off the means for pulling up the reference voltage sisal when the reference voltage signal reaches a predetermined voltage. ### Claim 16 (depends on 15) A reference voltage generator according to claim 15, wherein the means for generating a control signal can be disabled responsive to a boost signal. ### Claim 17 A method for generating a reference voltage signal comprising: applying power to a reference generator, thereby generating a reference voltage signal; switching on a pull-up stage coupled to the reference generator when the power is applied, thereby pulling up the reference voltage signal; and switching off the pull-up stage when the reference voltage signal reaches a predetermined voltage. ### Claim 18 (depends on 17) A method according to claim 17 further including: enabling a control voltage generator when the power is applied, thereby generating a control voltage signal; and comparing the control voltage signal to the reference voltage signal. ### Claim 19 (depends on 18) A method according to claim 18 further including disabling the control voltage generator when the voltage of the reference voltage signal equals the voltage of the control voltage signal.