Power Semiconductor Temperature Measurement with P-Well Isolation
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Solution Overview
Problem
Existing temperature measurement devices for power semiconductor devices face challenges in achieving high precision temperature detection with minimal adjustment, protecting the temperature sensor and detection circuit from damage, and maintaining a consistent voltage output proportional to temperature, due to fluctuations in current and dispersion issues with diffusion diodes.
Innovation Solution
A temperature measurement device featuring multiple temperature detecting diodes on a power semiconductor chip and a detection circuit on a separate integrated circuit chip, utilizing differential amplifiers and impedance configurations to stabilize voltage differences and prevent parasitic thyristor latch-up, with diodes connected through constant current or voltage sources and buffer amplifiers to ensure precise and continuous temperature measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a diffusion diode is formed on a silicon substrate and forward voltage is utilized for temperature sensing, then temperature detection function is achieved, but temperature detection accuracy is insufficient due to current fluctuation and PN junction manufacturing dispersion
Solution Approach 1:
A P-type well is introduced as an intermediary structure between the N-type substrate and the diffusion diode. This P-type well acts as a carrier barrier that prevents hole injection from the N-type substrate into the diffusion diode, thereby stabilizing the diode current and improving temperature detection accuracy without affecting the diode's temperature sensing function
Solution Approach 2:
The harmful effect of hole injection is extracted and isolated by creating a separate P-type well structure that specifically targets and blocks the hole flow path. This separates the temperature sensing function of the diffusion diode from the harmful parasitic current effect, allowing accurate temperature measurement
2Ease of manufacture
If temperature sensor and detection circuit are disposed on separate chips, then manufacturing cost is reduced, but dispersion effectively adds up leading to reduced measurement precision
Solution Approach 1:
The invention changes the electrical parameters of the diffusion diode by introducing the P-type well, which modifies the diode's current-voltage characteristics. This parameter change compensates for the dispersion effects caused by separate chip manufacturing, enabling accurate temperature measurement while maintaining the cost advantage of separate chip fabrication
3Measurement precision
If diffusion diode is used for temperature sensing, then temperature detection is achieved, but parasitic thyristor operation may occur causing sensor or circuit damage
Solution Approach 1:
The P-type well is预先 constructed as a protective barrier before the parasitic thyristor can be activated. By preemptively blocking the hole injection path into the diffusion diode, the structure prevents the conditions necessary for parasitic thyristor operation, thereby protecting both the temperature sensor and detection circuit from damage
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 enables high-precision temperature detection with reduced adjustment frequency, protects the temperature sensor and detection circuit from damage, and maintains a consistent voltage output proportional to temperature, effectively addressing the limitations of existing technologies.
Implementation Method 1
a temperature sensor that makes use of the temperature dependency of a forward voltage of a diffusion diode
Data Source
AI summary
A temperature measurement device of a power semiconductor device includes a plurality of temperature detecting diodes formed on a first chip having a power semiconductor device; and a detection circuit that is formed on a second chip having an integrated circuit that controls the power semiconductor device and is connected to the temperature detecting diodes; wherein the detection circuit detects a temperature of the power semiconductor device based on a difference between the forward voltages of the temperature detecting diodes when different values of current flow to the respective temperature detecting diodes.