Voltage-controlled delay element with programmable delay
First Claim
1. A programmable delay element comprising:
- a voltage controlled delay element having a delay period proportional to an analog control voltage;
control voltage determining means connected to said voltages controlled delay element for determining said analog control voltage; and
a plurality of programmable control voltage adjusting means connected to said control voltage determining means for modifying said analog control voltage in response to logic signals, wherein said control voltage determining means comprises;
a source path that sets a base current;
a control voltage generating path connected to said source path that determines said analog control voltage by running a source current that is proportional to said base current over a transistor; and
a gate path connected to said control voltage generating path for draining source current from said control voltage generating path and thereby adjusting said control voltage.
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Accused Products
Abstract
A voltage-controlled delay element utilizes a current-starved inverter configuration with a feedback path that ensures a rapid discharge of the storage node to ground once the desired delay time has elapsed. The circuit comprises a circuit path for charging the storage node (preferably rapidly), a first pull-down path capable of discharging the storage node at a rate determined by the control voltage, a second pull-down path capable of rapidly discharging the storage node, an output inverter, and a feedback connection between the output terminal of the output inverter and the second pull-down path to rapidly discharge the storage node when the output voltage starts rising. The circuit further comprises a means for programmably adjusting the delay in response to logic signals.
86 Citations
12 Claims
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1. A programmable delay element comprising:
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a voltage controlled delay element having a delay period proportional to an analog control voltage; control voltage determining means connected to said voltages controlled delay element for determining said analog control voltage; and a plurality of programmable control voltage adjusting means connected to said control voltage determining means for modifying said analog control voltage in response to logic signals, wherein said control voltage determining means comprises; a source path that sets a base current; a control voltage generating path connected to said source path that determines said analog control voltage by running a source current that is proportional to said base current over a transistor; and a gate path connected to said control voltage generating path for draining source current from said control voltage generating path and thereby adjusting said control voltage. - View Dependent Claims (3)
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2. A programmable delay element comprising:
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a voltage controlled delay element (VCDE); control voltage determining means connected to said VCDE for determining a control voltage; and a plurality of programmable control voltage adjusting means for modifying said control voltage in response to logic signals; wherein said control voltage determining means comprises; a first source path that sets a base current; a control voltage generating path connected to said first source path for determining said control voltage by running a source current that is proportional to said base current over a transistor; a gate path connected to said control voltage generating path for draining source current from said control voltage generating path and thereby adjusting said control voltage; wherein each of said programmable control voltage adjusting means comprises; an additional source path for receiving input signals from the control voltage determining means to set a second base current; a switching path coupled between said additional source path and a current sinking means for switching the programmable control voltage adjusting means on or off in response to one of said logic signals by connecting or not connecting said additional source path to said current sinking means; and wherein said current sinking means connected to said gate path drains a specified amount of current from said control voltage generating means when connected to said additional source path.
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4. A programmable delay element comprising:
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a circuit capable of producing an output signal that follows an input signal with a delay that is proportional to a control signal applied at a control signal input; a control signal determining circuit with an output operably connected to said control signal input and a load input; and a plurality of programmable control signal adjusting circuits operably connected to said load input for modifying said control signal in response to logic signals wherein said control signal determining circuit comprises; a source path that sets a base current; a control signal generating path connected to said source path that determines said control signal by running a source current that is proportional to said base current over a transistor; and a gate path connected to said control signal generating path for draining source current from said control signal generating path and thereby adjusting said control signal. - View Dependent Claims (5)
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6. A programmable delay element comprising:
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a circuit capable of producing an output signal that follows an input signal with a delay that is a function of a control signal applied at a control input; a base-mirror circuit with an output operably connected to said control input and a gate input; and a plurality of gate-mirror circuits operably connected to said base-mirror circuit via said gate input; wherein said base-mirror circuit comprises; a first source half of a first current-mirror circuit, said first source half having external reference signal inputs; a second current-mirror circuit comprising a second reference half operably connected to said first source half and a second source half; a third reference half of a third current-mirror circuit operably connected to said second source half, said third reference half connectable to a third source half in a gate-mirror circuit; and a gate path connected to said second source half for draining source current from said second source half. - View Dependent Claims (7, 8, 9, 10, 11, 12)
- 12. The programmable delay element according to claim 6 wherein said delay (T) is represented by the equation
- space="preserve" listing-type="equation">T=T.sub.0 +Q.sub.0 /I.sub.CTL
where T0 and Q0 are constants and ICTL is the value of a current signal determined by said control signal.
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Specification