Semiconductor device and control method thereof
View Patent ↗A semiconductor device including a program voltage supply circuit that supplies a drain of a memory cell with a program voltage, a detection circuit that refers to an output voltage of the program voltage supply circuit and detects a decrease of the program voltage supplied thereby, a frequency converting circuit that generates the clock signal by converting a frequency of a clock signal generated by an oscillator circuit into a lower frequency when the program voltage supplied by the program voltage supply circuit becomes equal to or lower than a given voltage, and a voltage generating circuit that generates a voltage supplied to a gate of the memory cell by using a clock signal, the frequency of which is converted by the frequency converting circuit. It is therefore possible to make the best use of the ability of the program voltage generating circuit in programming.
1. A semiconductor device comprising:
a program voltage supply circuit that supplies a drain of a memory cell with a program voltage; and
a voltage generating circuit that generates a voltage supplied to a gate of the memory cell by using a clock signal based on the program voltage supplied by the program voltage supply circuit.
2. The semiconductor device as claimed in claim 1 , wherein the voltage generating circuit uses, a clock signal having a lower and a higher frequency, and wherein the lower frequency is used when the program voltage supplied by the program voltage supply circuit becomes equal to or lower than a given voltage.
3. The semiconductor device as claimed in claim 1 , further comprising a frequency converting circuit that generates the clock signal by converting a frequency of a clock signal generated by an oscillator circuit into another frequency based on the program voltage supplied by the program voltage supply circuit.
4. The semiconductor device as claimed in claim 1 , further comprising a frequency converting circuit that generates the clock signal by converting a frequency of a clock signal generated by an oscillator circuit into a lower frequency when the program voltage supplied by the program voltage supply circuit becomes equal to or lower than a given voltage.
5. The semiconductor device as claimed in claim 1 , further comprising a detection circuit that refers to an output voltage of the program voltage supply circuit and detects a decrease of the program voltage supplied thereby.
6. The semiconductor device as claimed in claim 1 , further comprising a detection circuit that refers to an output current of the program voltage supply circuit and detects a decrease of the program voltage supplied thereby.
7. The semiconductor device as claimed in claim 3 , further comprising a circuit that generates a control signal for controlling the frequency of the clock signal converted by the frequency converting circuit in accordance with the program voltage supplied by the program voltage supply circuit.
8. The semiconductor device as claimed in claim 1 , wherein the voltage generating circuit generates the voltage supplied to the gate of the memory cell by a ramping manner.
9. The semiconductor device as claimed in claim 1 , wherein the voltage generating circuit comprises a diode type charge pump.
10. The semiconductor device as claimed in claim 1 , wherein the semiconductor device is a semiconductor memory device.
11. A method of controlling a semiconductor device comprising the steps of:
supplying a program voltage to a drain of a memory cell; and
generating a voltage supplied to a gate of the memory cell by using a clock signal determined based on the program voltage.
12. The method as claimed in claim 11 , further comprising a step of converting a frequency of a clock signal generated by an oscillator circuit into a lower frequency when the program voltage becomes equal to or lower than a given voltage, wherein the step of generating generates the voltage supplied to the gate of the memory cell by using the clock signal of the lower frequency.
13. The method as claimed in claim 11 , further comprising a step of detecting the program voltage by referring to an output voltage of a program voltage supply circuit that generates the program voltage.
14. The method as claimed in claim 11 , further comprising a step of detecting the program voltage by referring to an output current of a program voltage supply circuit that generates the program voltage.