OTP Readout Circuit Low-Voltage Data Access
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Solution Overview
Problem
In semiconductor devices with OTP circuits, data cannot be read out from OTP cells when the power source voltage is below a certain threshold, such as 2.1 V, due to varying reference voltages, preventing data retrieval and trimming operations.
Innovation Solution
A semiconductor device with a readout-possible signal output unit, utilizing a constant current source and current mirror circuit to generate a readout-possible voltage, allowing data to be read from OTP cells independently of the reset release signal and varying reference voltages, even at lower power source voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the reference voltage of the reference voltage source varies, then the reset release signal is not output to the control circuit and OTP circuit, but data can still be read out using a constant current source and current mirror circuit
Solution Approach 1:
The patent divides the voltage generation function into two independent parts: a reference voltage source for reset control and a constant current source for OTP readout. This segmentation allows the OTP readout to function independently of the reference voltage variations, resolving the contradiction between reliability and complexity by creating a dedicated readout path.
Solution Approach 2:
The current mirror circuit acts as an intermediary between the constant current source and the OTP cell. It converts the constant current into a readable voltage signal that is independent of the reference voltage, enabling reliable data readout even when the reference voltage varies or the reset release signal is not generated.
2Ease of operation
If the power source voltage is below 2.1 V, then the reset release signal is not output, but data can still be read out using the constant current source
Solution Approach 1:
The patent separates the reset control function (dependent on reference voltage) from the data readout function (dependent on constant current source). This allows data readout to occur independently of reset control, enabling operations at lower voltages where the reset release signal is not generated.
Solution Approach 2:
The constant current source provides self-contained power for OTP readout operations, independent of the main power supply voltage or reset control mechanisms. This self-service capability enables data readout to function reliably even when the overall system voltage is below the threshold for reset generation.
3Adaptability or versatility
If a constant current source and current mirror circuit are added, then data can be read out independently of reference voltage, but the device complexity increases
Solution Approach 1:
The constant current source and current mirror circuit serve multiple functions: they enable OTP readout at low voltages, provide reference-independent operation, and facilitate trimming operations. This multi-functionality justifies the added complexity by providing versatile operation across different voltage conditions.
Solution Approach 2:
The patent changes the operating parameter from reference-voltage-dependent to constant-current-dependent for OTP readout. By using the current mirror circuit to convert current to voltage, the system adapts to different power supply voltages and maintains reliable operation across a wider voltage range.
Data Source
AI summary
An OTP readout circuit includes an OTP circuit having a first OTP cell in which data is programmable only once, and a readout-possible signal output unit configured to generate a readout-possible voltage for reading out the data and output the generated readout-possible voltage to the OTP circuit. The readout-possible voltage from the readout-possible signal output unit causes the OTP circuit to read out the data programmed into the first OTP cell.