SEMICONDUCTOR DEVICE AND VARIATION INFORMATION OBTAINING PROGRAM

• US 20130257547A1
• Filed: 03/03/2013
• Published: 10/03/2013
• Est. Priority Date: 03/30/2012
• Status: Active Grant

• Current Assignee: Renesas Electronics Corporation
• Original Assignee: Renesas Electronics Corporation
• Inventors: Arai, Chihiro, Uozumi, Toshiya, Ueda, Keisuke
• Granted Patent: US 9,094,021 B2
• Time in Patent Office: Days
• US Class Current: 331/18
• CPC Class Codes: H03L 1/00 Stabilisation of generator output against variations of physical values, e.g. power supply
• CPC Class Codes: H03L 2207/06 Phase locked loops with a controlled oscillator having at least two frequency control terminals
• CPC Class Codes: H03L 7/06 using a reference signal applied to a frequency- or phase-locked loop
• CPC Class Codes: H03L 7/099 concerning mainly the controlled oscillator of the loop

Abstract

A conventional semiconductor device has a problem that acquisition of variation information of circuit elements constructing the semiconductor device is not easy. According to an embodiment, a semiconductor device has a control circuit which makes an oscillation circuit operate by at least two operation current values, obtains first frequency information related to frequency of an output signal corresponding to a first operation current value and second frequency information related to frequency of an output signal corresponding to a second operation current value, and obtains manufacture variation information of a circuit element on the basis of the difference between the first and second frequency information.

Claims

1. A semiconductor device comprising:

an oscillation circuit outputting an output signal having predetermined frequency; and

a control circuit outputting a current set value which switches operation current of the oscillation circuit between a first current value and a second current value,

wherein the control circuit obtains first frequency information related to frequency of the output signal in a state where the operation current is set to the first current value and second frequency information related to frequency of the output signal in a state where the operation current is set as the second current value, and obtains manufacture variation information of a circuit element as a component of the oscillation circuit on the basis of a difference value between the first and second frequency information.

2. The semiconductor device according to claim 1, wherein the control circuit corrects the current set value used for oscillating operation of the oscillation circuit on the basis of the manufacture variation information.

3. The semiconductor device according to claim 1, wherein the first frequency information is frequency of the output signal in a state where the operation current is set to the first current value, the second frequency information is frequency of the output signal in a state where the operation current is set to the second current value, and the control circuit corrects the current set value used for oscillation operation of the oscillation circuit on the basis of the frequency difference between first frequency obtained as the first frequency information and second frequency obtained as the second frequency information.

4. The semiconductor device according to claim 1, wherein the oscillation circuit has variable capacitance, frequency of the output signal is set according to a capacitance value of the variable capacitance, the control circuit outputs a capacitance selection value which designates the capacitance value of the variable capacitance and, in a period of obtaining the first frequency information and the second frequency information, the capacitance value of the variable capacitance is set to a value at which frequency of the output signal becomes maximum.

5. The semiconductor device according to claim 1, wherein the oscillation circuit has:

a phase difference comparator which outputs a phase difference detection value having magnitude according to a phase difference between a reference signal and a feedback signal generated from the output signal;

a filter circuit which performs filter process on the phase difference detection value to generate a frequency control value;

an oscillator which controls frequency of the output signal in accordance with the frequency control value;

a switch circuit provided between the filter circuit and the oscillator; and

a frequency divider for dividing frequency of the output signal to generate the feedback signal, and

in a period of obtaining the first and second frequency information, the control circuit sets the switch circuit in an off state to interrupt transmission of the frequency control value to the oscillator.

6. The semiconductor device according to claim 1, wherein the oscillation circuit has variable capacitance, frequency of the output signal is set according to a capacitance value of the variable capacitance, the control circuit outputs a capacitance selection value which designates the capacitance value of the variable capacitance, sets a target value of the frequency of the output signal, makes the oscillation circuit generate the output signal in a state where the operation current is set to the first current value, adjusts the capacitance selection value so that the frequency of the output signal becomes the target value, obtains, as the first frequency information, the capacitance selection value in a state where the frequency of the output signal becomes the target value, makes the oscillation circuit generate the output signal in a state where the operation current is set to the second current value, adjusts the capacitance selection value so that the frequency of the output signal becomes the target value, obtains, as the second frequency information, the capacitance selection value in a state where the frequency of the output signal becomes the target value, and corrects the current set value which is used for the oscillating operation of the oscillation circuit on the basis of a difference value between a first capacitance selection value obtained as the first frequency information and a second capacitance selection value obtained as the second frequency information.

7. The semiconductor device according to claim 1, further comprising a look-up table having table information indicating the relation between a variation amount of the Circuit element as a component of the oscillation circuit and the difference value,

wherein the control circuit obtains the manufacture variation information of the circuit element corresponding to the difference value with reference to the look-up table, and corrects the current set value used for oscillating operation of the oscillation circuit in accordance with the manufacture variation information obtained.

8. The semiconductor device according to claim 7, wherein the look-up table has a plurality of pieces of table information, and the table information used is switched on the basis of temperature information obtained from a temperature sensor formed on a substrate on which the semiconductor device is also formed or from the outside.

9. The semiconductor device according to claim 1, wherein the control circuit increases the current set value by process cycle, sets the frequency of the output signal obtained in a preceding cycle as the first frequency information, sets the frequency of the output signal obtained in a present cycle as the second frequency information and, in the case where second frequency obtained as the second frequency information decreases relative to first frequency obtained as the first frequency information, uses the current set value used in the preceding cycle for the oscillating operation of the oscillation circuit.

10. The semiconductor device according to claim 9, wherein the control circuit sets the current set value to the minimum value of the operation current and performs the first cycle in the process cycles.

11. The semiconductor device according to claim 1, further comprising a counter for measuring frequency of the output signal.

12. The semiconductor device according to claim 1, further comprising a reception circuit performing demodulating process using the output signal which is output from the oscillation circuit, and a transmission circuit performing modulating process using the output signal which is output from the oscillation circuit,

wherein each of the reception circuit and the transmission circuit has a correction circuit which generates a correction signal for the circuit itself on the basis of the manufacture variation information obtained by the control circuit.

13. A variation information obtaining program for obtaining manufacture variation information of a transistor in a semiconductor device comprising:

an oscillation circuit oscillating an output signal having predetermined frequency; and

a control circuit outputting a current set value which switches operation current of the oscillation circuit between a first current value and a second current value, and

the program for making the control circuit obtain first frequency information related to frequency of the output signal in a state where the operation current is set to the first current value, obtain second frequency information related to frequency of the output signal in a state where the operation current is set to the second current value, and obtain Manufacture variation information of a circuit element as a component of the oscillation circuit on the basis of a difference value between the first and second frequency information.