IO (Input/Output) circuit for accurate pull-down current
A current pulling and circuit technology, applied in the field of IO circuits, can solve problems such as large deviation of the pull-down current I, inconformity with communication signals, long completion time of the pull-down current I establishment time, etc., and achieve the effect of improving accuracy and shortening start-up time
Active Publication Date: 2012-05-09
SHANGHAI HUAHONG GRACE SEMICON MFG CORP
View PDF5 Cites 3 Cited by
- Summary
- Abstract
- Description
- Claims
- Application Information
AI Technical Summary
Problems solved by technology
The disadvantage of the existing IO circuit that can pull down the current is that the establishment time of the pull-down current I is relatively long, and the deviation of the pull-down current I is relatively large, which does not meet the requirements as a communication signal.
Method used
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View moreImage
Smart Image Click on the blue labels to locate them in the text.
Smart ImageViewing Examples
Examples
Experimental program
Comparison scheme
Effect test
Embodiment Construction
[0019] like image 3 Shown is a schematic structural diagram of an IO circuit that can pull down a precise current according to an embodiment of the present invention. The IO circuit capable of pulling down precise current in the embodiment of the present invention includes: a first resistor R1 , an electrostatic protection circuit for power supply, an electrostatic protection circuit for ground, and a pull-down current functional module. The first end of the first resistor R1 is connected to the pad PAD, the second end of the first resistor R1 is connected to the internal circuit of the chip, and the first resistor R1 is used for current limiting during electrostatic protection. The electrostatic protection circuit for the power supply is connected between the power supply VDD and the first terminal of the first resistor R1. The ground electrostatic protection circuit is connected between the ground and the first end of the first resistor R1. The pull-down current function ...
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More PUM
Login to View More Abstract
The invention discloses an IO (Input / Output) circuit for an accurate pull-down current. The IO circuit comprises a pull-down current functional module which comprises an operational amplifier, a second resistor, an NMOS (Negative Channel Metal Oxide Semiconductor) transistor and a switch module, wherein the second resistor, the NMOS transistor and the switch module are serially connected between a first resistor and the ground, an output end of the operational amplifier is connected with the grid electrode of the NMOS transistor, an anti-phase input end of the operational amplifier is connected with the second end of the second resistor, an in-phase input end of the operational amplifier is connected with a reference voltage, and the operational amplifier and the switch module are further connected with enable signals. When the enable signals are effective, the operational amplifier is formed in a negative feedback loop, the anti-phase input end of the operational amplifier is clamped to the reference voltage, the NMOS transistor is opened, the switch module is switched on, and the pull-down current is formed between the second end of the first resistor and the ground, wherein the size of the pull-down current is equal to the quotient of the reference voltage divided by the resistance of the second resistor. According to the IO circuit, the time for starting the pull-down current can be shortened, and the accuracy of the pull-down current is improved.
Description
technical field [0001] The invention relates to a semiconductor integrated circuit, in particular to an IO circuit capable of pulling down precise current. Background technique [0002] like figure 1 As shown, it is a schematic structural diagram of an existing IO circuit without a pull-down current. The existing IO circuit without a pull-down current includes: a resistor R, an electrostatic protection circuit for a power supply, and an electrostatic protection circuit for a ground. The first end of the resistor R is connected to the pad PAD, the second end of the resistor R is connected to the internal circuit of the chip, and the resistor R is used for current limiting during electrostatic protection. The electrostatic protection circuit for the power supply is connected between the power supply VDD and the first end of the resistor R. The ground electrostatic protection circuit is connected between the ground and the first end of the resistor R. The existing IO circuit...
Claims
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More Application Information
Patent Timeline
Login to View More Patent Type & Authority Applications(China)
IPC IPC(8): H03K19/0185
Inventor 骆川周平
Owner SHANGHAI HUAHONG GRACE SEMICON MFG CORP