LDO Current Limiting Circuit for RF Chip Bias Protection
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Solution Overview
Problem
Existing LDO circuits lack a current limiting function, leading to potential irreversible damage to radio frequency chips and devices due to high current working conditions, especially in complex application environments.
Innovation Solution
An LDO circuit with a current limiting function is designed, incorporating a bandgap reference circuit, error amplifier, feedback resistor network, and a current limiting module that includes a load current mirror, reference current unit, current comparison unit, hysteresis shaping unit, and control current output unit to regulate and limit output current based on load conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If LDO circuit provides high current output to meet increasing radio frequency chip power requirements, then power delivery capability is improved, but risk of device damage and system failure increases due to overheating and burnout
Solution Approach 1:
The patent applies preliminary anti-action by implementing a current limiting function module that proactively prevents excessive current before it can cause damage. The module includes a current detection unit that continuously monitors output current and a limiting unit that activates when current exceeds a threshold, thereby preemptively protecting the radio frequency chip and other devices from burnout and overheating while still allowing high current operation within safe limits
2Reliability
If LDO circuit adds current limiting function module to protect devices, then device reliability is improved, but circuit complexity increases due to additional components
Solution Approach 1:
The patent applies merging by integrating the current limiting function module with the existing LDO circuit architecture. The current detection unit utilizes the existing output node, and the limiting unit works in conjunction with the power transistor and feedback network already present in the LDO. This combining approach adds protection functionality while minimizing the increase in overall circuit complexity compared to implementing separate protection circuits
Data Source
AI summary
Provided are an LDO circuit having a current limiting function, and a chip and an electronic device. The LDO circuit comprises a bandgap reference circuit (101), an error amplifier (102), a power transistor (103), a feedback resistor network (104), and a current limiting function module (105), wherein the current limiting function module (105) comprises a load current mirror unit (107), a reference current unit (108), a current comparison unit (109), a hysteresis shaping unit (110), and a control current output unit (111). The current limiting function module (105) controls the on or off of a negative feedback loop and a current limiting output unit in the LDO circuit by comparing a load current with a reference current, so as to control an output current, thereby providing a stable direct current bias voltage for a radio frequency chip under working conditions such as large power and a complex application environment.