Power-On Reset Circuit Using PTAT-CTAT Trip Voltage Control
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Solution Overview
Problem
Conventional power-on reset circuits face challenges with increased current consumption as supply voltage scales up, leading to larger and more costly electronic systems due to the need for high resistance resistors for current compensation.
Innovation Solution
The power-on reset circuit employs PTAT and CTAT circuits to generate control voltages that are independent of the supply voltage, eliminating the need for significant resistance resistors and thereby reducing the size and manufacturing cost of the circuit and the associated electronic system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the supply voltage is scaled up, then the power handling capability is improved, but the current in the power-on reset circuit increases
Solution Approach 1:
The patent changes the resistance values of resistors R1 and R2 to be smaller than conventional values (e.g., 10 mega-ohms). This parameter change allows the circuit to handle higher supply voltages while maintaining controlled current levels through the revised resistor network configuration.
Solution Approach 2:
The patent introduces a current compensation mechanism using resistors R1 and R2 that preemptively counteracts the current increase caused by higher supply voltages. The compensation current generated through these resistors opposes the harmful current increase, allowing the circuit to operate at higher voltages without excessive current consumption.
2Use of energy by moving object
If resistors of significant resistance values are utilized to compensate for increased current, then the current control is improved, but the size and manufacturing cost increase
Solution Approach 1:
The patent reduces the resistance values of resistors R1 and R2 from conventional significant values (e.g., 10 mega-ohms) to smaller values. This parameter change achieves current compensation while reducing the physical size and manufacturing cost of the resistors, making the power-on reset circuit more compact and cost-effective.
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
This solution ensures that the current in the power-on reset circuit remains independent of the supply voltage, eliminating the need for current compensation techniques and resulting in a significantly smaller and less costly power-on reset circuit and electronic system.
Implementation Method 1
The power-on reset circuit includes a first proportional-to-absolute-temperature (PTAT) circuit configured to output first and second PTAT voltages
Implementation Method 2
a complementary-to-absolute-temperature (CTAT) circuit configured to output a control voltage based on the first PTAT voltage, the second PTAT voltage, and the supply voltage
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
A power-on reset circuit (104) includes a complementary-to-absolute-temperature circuit, CTAT, (204) that outputs one control voltage (VC1), and a proportional-to-absolute-temperature, PTAT, circuit (202) that outputs a PTAT current (I1, I2). The power-on reset circuit further includes various resistors (R1, R2) that are coupled in series and generate another control voltage (VC2) based on the PTAT current that is outputted by the PTAT circuit (202). Further, the power-on reset circuit includes a comparator (206) that compares the two control voltages to generate a power-on reset signal (PS). The power-on reset signal is activated when a supply voltage (VDD) is greater than or equal to a trip voltage and deactivated when the supply voltage is less than the trip voltage. A functional circuit is configured to execute a reset operation associated therewith when the power-on reset signal transitions from a deactivated state to an activated state.