Reference voltage generation circuit and pipe line analog-to-digital converter using the same

• US 7,501,972 B2
• Filed: 07/05/2007
• Issued: 03/10/2009
• Est. Priority Date: 08/10/2006
• Status: Expired due to Fees

• Current Assignee: Oki Semiconductor Company Limited (ROHM Co., Ltd.)
• Original Assignee: Oki Semiconductor Company Limited (ROHM Co., Ltd.)
• Inventors: Wakamatsu, Takeshi
• Primary Examiner(s): Nguyen; Khai M
• Application Number:
  US11/822,329
• Publication Number:
  US 20080036639A1
• Time in Patent Office: 614 Days
• Field of Search: 341/154, 341161-163, 323/313
• US Class Current: 341/155
• CPC Class Codes: H03M 1/0695 using less than the maximum number of output states per stage or step, e.g. 1.5 per stage or less than 1.5 bit per stage type
• CPC Class Codes: H03M 1/167 all stages comprising simultaneous converters H03M1/165 takes precedence
• CPC Class Codes: H03M 1/44 Sequential comparisons in series-connected stages with change in value of analogue signal

Abstract

A reference voltage generation circuit for a plurality of reference generation voltages and a pipe line analog-to-digital converter (ADC) using the same are provided. The reference voltage generation circuit including a charging capacitor for stabilizing the reference voltages charges the charging capacitor prior to the generation of the reference voltages, thus decreasing the time for the pipe line ADC to operate stably.

Claims

1. A reference voltage generation circuit comprising:

a reference voltage generation part for generating a plurality of reference voltages on corresponding reference voltage output terminals including first and second reference voltage output terminals, said first reference voltage output terminal being connected to one terminal of a charging capacitor and said second reference voltage output terminal being connected to the other terminal of said charging capacitor; and

a charging and switching part for disconnecting said charging capacitor from said reference voltage generation part so as to charge said charging capacitor and thereafter for stopping charging of said charging capacitor and connecting said charging capacitor to said reference voltage generation part in response to a terminal voltage of said charging capacitor;

wherein charging of said charging capacitor is started prior to generations of said reference voltages.

2. A reference voltage generation circuit, comprising:

a reference voltage generation part for generating a plurality of reference voltages on corresponding reference voltage output terminals including first and second reference voltage output terminals, said first reference voltage output terminal being connected to one terminal of a charging capacitor and said second reference voltage output terminal being connected to the other terminal of said charging capacitor; and

a charging and switching part for disconnecting said charging capacitor from said reference voltage generation part so as to charge said charging capacitor and thereafter for stopping charging of said charging capacitor and connecting said charging capacitor to said reference voltage generation part in response to a terminal voltage of said charging capacitor;

wherein charging of said charging capacitor is started prior to generations of said reference voltages, and

wherein

said charging and switching part is controlled by a power down control signal having first and second logic levels, and

said charge and switching part comprises

a discharge switch connected to said one terminal of said charging capacitor for discharging said charging capacitor in response to said first logic level,

a charging control circuit connected to said one terminal of said charging capacitor for generating a first charging control signal when a voltage on said one terminal of said charging capacitor is equal to or lower than a predetermined voltage and for generating a second charging control signal when said voltage on said one terminal of said charging capacitor is higher than said predetermined voltage,

a charging circuit connected to said charging control circuit and said one terminal of said charging capacitor for generating a charging voltage to said charging capacitor via said one terminal of said charging capacitor in response to said second logic level and said first charging control signal and for stopping a supply of said charging voltage in response to said second charging control signal,

a switch connected across said reference voltage generation part and said charging capacitor for disconnecting said charging capacitor from said reference voltage generation part in response to said first charging control signal and for connecting said charging capacitor to said reference voltage generation part in response to said second charging control signal.

3. A reference voltage generation circuit according to claim 2, wherein said charging control circuit is configured by an inverter.

4. A pipe line analog-to-digital converter including a reference voltage generation circuit according to claim 2,

wherein said pipe line analog-to-digital converter further comprises an analog-to-digital conversion part for converting analog signals to digital signals on the basis of said reference voltages.

5. A reference voltage generation circuit, comprising:

a reference voltage generation part for generating a plurality of reference voltages on corresponding reference voltage output terminals including first and second reference voltage output terminals, said first reference voltage output terminal being connected to one terminal of a charging capacitor and said second reference voltage output terminal being connected to the other terminal of said charging capacitor; and

a charging and switching part for disconnecting said charging capacitor from said reference voltage generation part so as to charge said charging capacitor and thereafter for stopping charging of said charging capacitor and connecting said charging capacitor to said reference voltage generation part in response to a terminal voltage of said charging capacitor;

wherein charging of said charging capacitor is started prior to generations of said reference voltages, and

said charging and switching part is controlled by a power down control signal having first and second logic levels, and

said charge and switching part comprises;

a charging circuit responsive to said terminal voltage for generating a charging voltage to said charging capacitor in respond to said first logic level and for stopping a supply of said charging voltage in response to said terminal voltage; and

a switch connected across said reference voltage generation part and said charging capacitor for disconnecting said charging capacitor from said reference voltage generation part in response to said first logic level and for connecting said charging capacitor to said reference voltage generation part in response to said second logic level.

6. A pipe line analog-to-digital converter comprising a reference voltage generation circuit according to claim 5,

wherein said pipe line analog-to-digital converter further comprises an analog-to-analog conversion part for converting analog signals to digital signals on the basis of said reference voltages.

7. A reference voltage generation circuit, comprising:

a reference voltage generation part for generating a plurality of reference voltages on corresponding reference voltage output terminals including first and second reference voltage output terminals, said first reference voltage output terminal being connected to one terminal of a charging capacitor and said second reference voltage output terminal being connected to the other terminal of said charging capacitor; and

a charging and switching part for disconnecting said charging capacitor from said reference voltage generation part so as to charge said charging and thereafter for stopping charging of said charging capacitor and connecting said charging capacitor to said reference voltage generation part in response to a terminal voltage of said charging capacitor;

wherein charging of said charging capacitor is started prior to generations of said reference voltages,

wherein said charging and switching part is controlled by a power down control signal having first and second logic levels, and

wherein

said charging and switching part comprises;

a charging control circuit connected to said terminal voltage for generating a first charging control signal when said terminal voltage of said charging capacitor is equal to or lower than a predetermined voltage and for generating a second charging control signal when said terminal voltage of said charging capacitor is higher than said predetermined voltage;

a charging circuit responsive to said terminal voltage and said charging control circuit for generating a charging voltage to said charging capacitor in respond to said first charging control signal and for stopping a supply of said charging voltage in response to said second charging control signal; and

a switch connected across said reference voltage generation part and said charging capacitor for disconnecting said charging capacitor from said reference voltage generation part in response to said first logic level and for connecting said charging capacitor to said reference voltage generation part in response to said second logic level.

8. A reference voltage generation circuit according to claim 7, wherein said charging control circuit is configured by an inverter.

9. A pipe line analog-to-digital converter comprising a reference voltage generation circuit according to claim 7,

wherein said pipe line analog-to-digital converter further comprises an analog-to-digital conversion part for converting analog signals to digital signals on the basis of said reference voltages.

10. A pipe line analog-to-digital converter, comprising;

a reference voltage generation circuit including a reference voltage generation part for generating a plurality of reference voltages on corresponding reference voltage output terminals, having a first and second reference voltage output terminals, said first reference voltage output terminal being connected to one terminal of a charging capacitor and said second reference voltage output terminal being connected to the other terminal of said charging capacitor, and a charging and switching part for disconnecting said charging capacitor from said reference voltage generation part so as to charge said charging capacitor and thereafter for stopping charging of said charging capacitor and connecting said charging capacitor to said reference voltage generation part in response to a terminal voltage of said charging capacitor; and

an analog-to-digital conversion part for converting analog signals to digital signals on the basis of said reference voltages,

wherein charging of said charging capacitor is started prior to generating said reference voltages.

11. A pipe line analog-to-digital converter according to claim 10,

wherein

said charging and switching part is controlled by a power down control signal having first and second logic levels, and

said charge and switching part comprises:

a discharge switch connected to said one terminal of said charging capacitor for discharging said charging capacitor in response to said first logic level;

a charging control circuit connected to said one terminal of said charging capacitor for generating a first charging control signal when a voltage on said one terminal of said charging capacitor is equal to or lower than a predetermined voltage and for generating a second charging control signal when said voltage on said one terminal of said charging capacitor is higher than said predetermined voltage;

a charging circuit connected to said charging control circuit and said one terminal of said charging capacitor for generating a charging voltage to said charging capacitor via said one terminal one terminal of said charging capacitor in respond to said second logic level and said first charging control signal and for stopping a supply of said charging voltage in response to said second charging control signal; and

a switch connected across said reference voltage generation part and said charging capacitor for disconnecting said charging capacitor from said reference voltage generation part in response to said first charging control signal and for connecting said charging capacitor to said reference voltage generation part in response to said second charging control signal.

12. A pipe line analog-to-digital converter according to claim 11, wherein said charging control circuit is an inverter.

13. A pipe line analog-to-digital converter according to claim 10,

wherein

said charging and switching part is controlled by a power down control signal having first and second logic levels, and

said charge and switching part comprises:

a charging circuit connected to said terminal voltage for generating a charging voltage to said charging capacitor in respond to said first logic level and for stopping a supply of said charging voltage in response to said terminal voltage; and

a switch connected across said reference voltage generation part and said charging capacitor for disconnecting said charging capacitor from said reference voltage generation part in response to said first logic level and for connecting said charging capacitor to said reference voltage generation part in response to said second logic level.

14. A pipe line analog-to-digital converter according to claim 10,

wherein

said charging and switching part is controlled by a power down control signal having first and second logic levels, and

said charge and switching part comprises:

a charging control circuit connected to said terminal voltage for generating a first charging control signal when said terminal voltage of said charging capacitor is equal to or lower than a predetermined voltage and for generating a second charging control signal when said terminal voltage of said charging capacitor is higher than said predetermined voltage;

a charging circuit connected to said terminal voltage and said charging control circuit for generating a charging voltage to said charging capacitor in respond to said first charging control signal and for stopping a supply of said charging voltage in response to said second charging control signal; and

a switch connected across said reference voltage generation part and said charging capacitor for disconnecting said charging capacitor from said reference voltage generation part in response to said first logic level and for connecting said charging capacitor to said reference voltage generation part in response to said second logic level.

15. A pipe line analog-to-digital converter according to claim 14, wherein said charging control circuit is an inverter.