DA converter circuit provided with DA converter of segment switched capacitor type
First Claim
1. A DA converter circuit including a DA converter of segment switched capacitor type, said DA converter comprising:
- (a) an operational amplifier having a feedback capacity, (b) a plurality of M=2L capacitors which are connected in parallel to each other so as to supply electric charges to the operational amplifier;
(c) an electrically charging switch for switching over between performing and not performing of electrically charging electric charges onto the respective capacitors; and
(d) an electrically discharging switch for switching over between performing and not performing of electrically discharging electric charges from the respective capacitors, and wherein the DA converter circuit further comprises;
a switch device for performing either one of the electrically charging, the electrically discharging, grounding, and polarity inversion onto the respective capacitors; and
a controller for controlling the electrically charging switch, the electrically discharging switch and the switch device so as to execute a process of second-order DWA algorithm for performing a second-order noise shaping of a non-linearity of the DA converter circuit for a low-pass Δ
Σ
AD modulator, using the following operations;
(A) a “
+2”
operation for performing the electrically charging and the electrically discharging twice onto the respective capacitors for a predetermined time interval to generate an output voltage which is a voltage of +2 times a predetermined reference output voltage;
(B) a “
+1”
operation for performing the electrically charging and the electrically discharging once onto the respective capacitors for the time interval to generate an output voltage which is a voltage of +1 times the reference output voltage;
(C) a “
0”
operation for not performing any electrically charging and electrically discharging onto the respective capacitors for the time interval to generate an output voltage which is a voltage of a grounding electric potential; and
(D) a “
−
1”
operation for performing the electrically charging once onto the respective capacitors and thereafter inverting polarities of the respective capacitors for the time interval to generate an output voltage which is a voltage of −
1 times the reference output voltage.
1 Assignment
0 Petitions
Accused Products
Abstract
A DA converter circuit is provided for use in a ΔΣ AD modulator. The DA converter circuit includes a DA converter of segment switched capacitor type. The DA converter includes an operational amplifier, capacitors as connected in parallel to each other to supply electric charges to the operational amplifier, an electrically charging switch for switching of electrically charging electric charges onto the respective capacitors or not, and an electrically discharging switch for switching or not electrically discharging electric charges from the respective capacitors or not. A switch device performs either one of the electrically charging, the electrically discharging, grounding, and polarity inversion onto the respective capacitors. A controller controls the electrically charging switch, the electrically discharging switch and the switch device to execute a process of second-order DWA algorithm for performing a second-order noise shaping of a non-linearity of the DA converter circuit.
-
Citations
8 Claims
-
1. A DA converter circuit including a DA converter of segment switched capacitor type, said DA converter comprising:
-
(a) an operational amplifier having a feedback capacity, (b) a plurality of M=2L capacitors which are connected in parallel to each other so as to supply electric charges to the operational amplifier;
(c) an electrically charging switch for switching over between performing and not performing of electrically charging electric charges onto the respective capacitors; and
(d) an electrically discharging switch for switching over between performing and not performing of electrically discharging electric charges from the respective capacitors, and wherein the DA converter circuit further comprises;
a switch device for performing either one of the electrically charging, the electrically discharging, grounding, and polarity inversion onto the respective capacitors; and
a controller for controlling the electrically charging switch, the electrically discharging switch and the switch device so as to execute a process of second-order DWA algorithm for performing a second-order noise shaping of a non-linearity of the DA converter circuit for a low-pass Δ
Σ
AD modulator, using the following operations;
(A) a “
+2”
operation for performing the electrically charging and the electrically discharging twice onto the respective capacitors for a predetermined time interval to generate an output voltage which is a voltage of +2 times a predetermined reference output voltage;
(B) a “
+1”
operation for performing the electrically charging and the electrically discharging once onto the respective capacitors for the time interval to generate an output voltage which is a voltage of +1 times the reference output voltage;
(C) a “
0”
operation for not performing any electrically charging and electrically discharging onto the respective capacitors for the time interval to generate an output voltage which is a voltage of a grounding electric potential; and
(D) a “
−
1”
operation for performing the electrically charging once onto the respective capacitors and thereafter inverting polarities of the respective capacitors for the time interval to generate an output voltage which is a voltage of −
1 times the reference output voltage. - View Dependent Claims (2, 3, 4)
-
-
5. A Δ
- Σ
AD modulator comprising;
a DA converter circuit;
a subtracter for subtracting a signal outputted from the DA converter circuit from an inputted analogue signal and outputting a signal having a subtraction result;
a low-pass filter for performing a predetermined low-pass filtering process onto the analogue signal outputted from the subtracter and outputting a filtered signal; and
an AD converter circuit for AD-converting the analogue signal outputted from the low-pass filter into a digital signal and outputting the AD-converted digital signal and further outputting the digital signal to the subtracter via the DA converter circuit, wherein said DA converter circuit includes a DA converter of segment switched capacitor type, wherein said DA converter comprising;
(a) an operational amplifier having a feedback capacity;
(b) a plurality of M=2L capacitors which are connected in parallel to each other so as to supply electric charges to the operational amplifier;
(c) an electrically charging switch for switching over between performing and not performing of electrically charging electric charges onto the respective capacitors; and
(d) an electrically discharging switch for switching over between performing and not performing of electrically discharging electric charges from the respective capacitors, and wherein the DA converter circuit further comprises;
a switch device for performing either one of the electrically charging, the electrically discharging operation, grounding, and polarity inversion onto the respective capacitors; and
a controller for controlling the electrically charging switch, the electrically discharging switch and the switch device so as to execute a process of second-order DWA algorithm for performing a second-order noise shaping of a non-linearity of the DA converter circuit for a low-pass Δ
Σ
AD modulator, using the following operations;
(A) a “
+2”
operation for performing the electrically charging and the electrically discharging twice onto the respective capacitors for a predetermined time interval to generate an output voltage which is a voltage of +2 times a predetermined reference output voltage;
(B) a “
+1”
operation for performing the electrically charging and the electrically discharging once onto the respective capacitors for the time interval to generate an output voltage which is a voltage of +1 times the reference output voltage;
(C) a “
0”
operation for not performing any electrically charging and electrically discharging onto the respective capacitors for the time interval to generate an output voltage which is a voltage of a grounding electric potential; and
(D) a “
−
1”
operation for performing the electrically charging once onto the respective capacitors and thereafter inverting polarities of the respective capacitors for the time interval to generate an output voltage which is a voltage of −
1 times the reference output voltage. - View Dependent Claims (6, 7, 8)
- Σ
Specification