Current Sense Circuit Switching for 1V-40V Voltage Detection
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Solution Overview
Problem
Current current sense circuits face challenges in supporting a wide input voltage range, particularly struggling to accurately detect current at both high and low voltage applications, with traditional solutions requiring complex and power-consuming dual circuit structures.
Innovation Solution
A signal processing apparatus with a high voltage circuit and a bypass circuit that automatically adjusts based on the input voltage, using PMOS transistors for high voltage and NMOS transistors for low voltage scenarios, allowing the current sense circuit to operate effectively from 1V to 40V.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional current sense circuit is used, then it can accurately detect current at low voltage, but it cannot withstand high voltage stress
Solution Approach 1:
The circuit dynamically switches between high voltage mode and low voltage mode based on the input voltage level. The control circuit detects the voltage level and activates the appropriate circuit path, enabling the system to adapt to different voltage conditions and achieve both high voltage withstanding capability and wide voltage range coverage
Solution Approach 2:
The current sense circuit is divided into two separate paths: a high voltage current sense circuit for high voltage detection and a low voltage current sense circuit for low voltage detection. Each path is optimized for its specific voltage range, allowing the system to maintain accuracy across the entire voltage spectrum while ensuring reliable high voltage withstanding capability
2Reliability
If a high voltage current sense circuit is used, then it can withstand high voltage, but it increases device complexity and power consumption
Solution Approach 1:
The control circuit dynamically selects the active current sense path based on voltage detection. When high voltage is detected, the high voltage current sense circuit is activated; when low voltage is detected, the low voltage current sense circuit is activated. This dynamic switching reduces the effective circuit complexity at any given moment while maintaining high voltage withstanding capability when needed
Solution Approach 2:
The high voltage withstanding functionality is extracted into a separate high voltage current sense circuit that is only activated when needed. This allows the main low voltage circuit to remain simple while providing high voltage capability on demand, reducing overall device complexity while maintaining reliability
3Reliability
If a high voltage current sense circuit is used, then it can withstand high voltage, but it increases power consumption
Solution Approach 1:
The circuit dynamically activates only the necessary current sense path based on the input voltage level. The control circuit monitors the voltage and switches between high voltage and low voltage paths, ensuring that the high power-consuming high voltage circuit is only active when high voltage is present, thereby reducing overall power consumption while maintaining high voltage withstanding capability
Solution Approach 2:
The high voltage current sense circuit is extracted as a separate, independently controllable module. This allows the system to disable the high voltage path when not needed, eliminating its power consumption during low voltage operation while preserving the capability to withstand high voltage when required
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 a simple, reliable, and efficient current detection across a wide voltage range, reducing chip area and power consumption, and ensuring accurate current sensing in automotive applications.
Implementation Method 1
PMOS transistors for high voltage and NMOS transistors for low voltage scenarios, allowing the current sense circuit to operate effectively from 1V to 40V
Implementation Method 2
A signal processing apparatus with a high voltage circuit and a bypass circuit that automatically adjusts based on the input voltage
Implementation Method 3
An amplifier U1 has a non-inverting input connected to a first terminal of Rsns through R1, and an inverting input connected to a second terminal of Rsns. The amplifier U1 controls the current I1 such that the voltage across Rsns is the same as the voltage across R1
Implementation Method 4
The current sense circuit further comprises a current mirror formed by transistors MN1 and MN2. A gate of MN1 and a gate of MN2 are connected together and further connected to an output of the amplifier U1
Data Source
AI summary
A signal processing apparatus includes a signal processing circuit configured to process a signal obtained from a voltage bus, a high voltage circuit configured to withstand a voltage stress when a high voltage is applied to the voltage bus, and a bypass circuit configured to bypass the high voltage circuit when a low voltage is applied to the voltage bus.