Bidirectional Transceiver ODT Timing for Power-Supply Noise Control
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Solution Overview
Problem
In semiconductor integrated circuits, power-supply noise on bidirectional signal lines causes inaccuracies in data transmission and reception due to sudden fluctuations in power supply voltage, especially when the receiver circuit switches off the ODT function, affecting subsequent data transmission.
Innovation Solution
A semiconductor integrated circuit with a termination circuit comprising a resistor and a switch, controlled by a control circuit to manage the ODT function, ensuring it remains on for a predetermined period after data reception to reduce power-supply noise, thereby enabling accurate data transmission and reception.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the receiver circuit switches off the ODT function after receiving data, then power consumption is reduced, but power-supply noise occurs on the bidirectional signal line causing data transmission inaccuracies
Solution Approach 1:
The control circuit keeps the ODT function turned on for a predetermined period after data reception as a preliminary measure to prevent power-supply noise before it can affect subsequent data transmission. This proactive approach ensures that when the receiver switches back to receiving mode, the termination resistance is already in place to suppress noise, thus maintaining data transmission accuracy while allowing temporary power consumption increase only when necessary.
2Reliability
If the ODT function is switched on continuously to prevent power-supply noise, then data transmission accuracy is maintained, but power consumption increases
Solution Approach 1:
The ODT function is activated periodically rather than continuously - specifically, it remains on for a predetermined period after data reception and is turned off during intervals when no data transmission is expected. This periodic switching strategy maintains data transmission accuracy during critical periods while reducing overall power consumption during idle periods, optimally balancing reliability and energy efficiency.
3Speed
If the receiver switches off the ODT function quickly after receiving data, then switching speed is improved, but power-supply noise affects subsequent data reception
Solution Approach 1:
The control circuit anticipates the need for ODT function by keeping it activated for a predetermined period after data reception. This preliminary action ensures that the termination resistance is already in place before the receiver switches back to receiving mode, preventing power-supply noise from affecting subsequent data reception while maintaining fast switching capability during the active period.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively reduces power-supply noise, allowing for accurate data transmission and reception by maintaining the ODT function on during data reception intervals, preventing noise interference from switching states.
Implementation Method 1
a first termination circuit that includes a first resistor and a first switch, the first resistor being provided between a first power supply terminal and the signal line, the first switch controlling a current flowing through the first resistor
Data Source
AI summary
Provided is a semiconductor integrated circuit according to an exemplary aspect of the present invention including first and second transmitter-receivers that execute transmission and reception of data through a signal line. The first transmitter-receiver includes a first termination circuit that includes a first resistor and a first switch, the first resistor being provided between a first power supply terminal and the signal line, the first switch controlling a current flowing through the first resistor to be turned on and off, and a control circuit that outputs a first control signal to the first termination circuit so that the first switch is turned on when the first transmitter-receiver receives data, the first switch is turned off when the first transmitter-receiver transmits the data, and the first switch is continuously on during a first predetermined period after receiving the data when the first transmitter-receiver further receives another data after receiving the data.