Controllable idle time current mirror circuit for switching regulators, phase-locked loops, and delay-locked loops
View Patent ↗The four types of the controllable idle time current mirror circuits are presented with an improvement in productivity, performance, cost, chip area, power consumption, and design time. The controllable idle time current mirror circuits basically include a sensing block, triggering transistors, current mirror, current source, a n-bit control circuit array, and a feedback line. If the sensing voltage does not reach the expected voltage compared to the midpoint voltage of the sensing gate, the triggering transistors provide a current to its output through the current mirror until the voltage at feedback reaches the midpoint voltage. Time to reach the midpoint voltage at a load is simply equal to the charge stored at the load divided by the total current, which is controlled by an N-bit digital input and a device aspect ratio of each triggering transistor. Consequently, all controllable idle time current mirror circuits provide a controllable reduction in the difference between the initial condition and the expected condition in order to solve many drawbacks simultaneously. In addition, all the controllable idle time current mirror circuits within applied systems control how fast the applied systems come into regulation or lock. Thus, all the controllable idle time current mirror circuits presented achieve a fast controllable lock-in time, a short controllable start-up time, a controllable reduction in power and time, a significant reduction in design simulation time, an improvement in productivity, and a higher performance.
1. A controllable idle time current mirror circuit for making delay-locked loop become intelligently locked, comprising:
a feedback line connected with the output and input of the controllable idle time current mirror circuit and also coupled to a filter;
a sensing inverter for sensing a voltage at the feedback line and comparing with a midpoint voltage decided by device aspect ratios of the sensing inverter;
n-bit current-scaling binary-weighted control circuit array for generating a total current corresponding to an N-bit digital input and a device aspect ratio of each triggering transistor;
a current mirror for receiving a total current and providing the current to the feedback line; and
a current source coupled to the feedback line.
2. The circuit as recited in claim 1 wherein power-down inverter and power-down transistors are further added to turn off all transistors and CMOS gates so that no current flows into the circuit during power-down mode.
3. The circuit as recited in claim 1 wherein an odd number of CMOS sensing inverters control the gates of triggering NMOS transistors coupled to the PMOS transistor current mirror.
4. The circuit as recited in claim 1 wherein an odd number of CMOS sensing inverters control the gates of triggering PMOS transistors coupled to the NMOS transistor current mirror.
5. The circuit as recited in claim 1 wherein an even number of CMOS sensing inverters directly control the gate of NMOS transistor if additional triggering transistors and current mirror are not added on the other control path.
6. The circuit as recited in claim 1 wherein an even number of CMOS sensing inverters directly control the gate of PMOS transistor if additional triggering transistors and current mirror are not added on the other control path.
7. The circuit as recited in claim 1 wherein the sensing inverter is comparator.
8. The circuit as recited in claim 1 wherein the sensing inverter is operational amplifier.
9. The circuit as recited in claim 1 wherein the sensing inverter is CMOS NAND gate since the two-input CMOS NAND gate can be used as an enabling inverter with one input serving as an active high enable input and the other used as the sensing input.
10. The circuit as recited in claim 1 wherein the sensing inverter is CMOS NOR gate since the two-input CMOS NOR gate can be used as an enabling inverter with one input serving as an active low enable input and the other used as the sensing input.
11. The circuit as recited in claim 1 wherein the sensing inverter is a lower-voltage sensing inverter for sensing a voltage at the feedback line and comparing with the lower midpoint voltage.
12. The circuit as recited in claim 1 wherein the sensing inverter is a higher-voltage sensing inverter for sensing a voltage at the feedback line and comparing with the higher midpoint voltage.
13. The circuit as recited in claim 1 wherein the sensing inverter is both higher-voltage sensing inverter and lower-voltage sensing inverter.
14. The circuit as recited in claim 1 wherein capacitors are added to necessary nodes.
15. The circuit as recited in claim 1 wherein the current mirror is the Wilson current mirror.
16. The circuit as recited in claim 1 wherein the current mirror is cascode current mirror.
17. The circuit as recited in claim 1 wherein the current mirror is simple current mirror.
18. The circuit as recited in claim 1 wherein the controllable idle time current mirror circuit is applied to all types of delay-locked loops without regard to architectures and schematics.