PA Voltage Protection Circuit for Battery Drop Shutdown Timing
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Solution Overview
Problem
The increasing current demands of 5G smartphones lead to voltage drops due to internal battery resistance and PMIC/PCB resistance, causing unstable power supply to power amplifiers (PAs), which can result in PA burnout if the switching sequence is not properly managed.
Innovation Solution
A voltage protection circuit that turns off the PA earlier than the switch in response to deviations in battery voltage, ensuring the PA receives a controlled bias current and preventing burnout by forwarding a main control signal from the voltage protection circuit to the bias control unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the maximum allowable current is increased to support 5G functions, then the power supply capability is improved, but voltage drop occurs due to internal resistance causing PA burnout
Solution Approach 1:
The voltage protection circuit monitors battery voltage in advance and generates a control signal to turn off the PA before the voltage drop causes burnout. This preliminary action prevents the harmful effect from occurring by detecting the voltage threshold and initiating protective measures proactively.
Solution Approach 2:
The voltage protection circuit acts as an intermediary between the battery and the PA. It monitors the battery voltage and controls the PA's operation based on the voltage status, preventing direct harmful effects from reaching the PA while allowing normal operation when voltage is sufficient.
2Loss of energy
If the switch is turned off first during voltage drop, then the power consumption is reduced, but the PA burnout risk increases due to improper switching sequence
Solution Approach 1:
The voltage protection circuit generates a control signal to turn off the PA before the switch is turned off. This preliminary action ensures the PA is protected from voltage drop effects before the switching operation occurs, preventing burnout while still achieving power reduction.
Solution Approach 2:
The control signal from the voltage protection circuit applies a counter-action by turning off the PA in advance, offsetting the potential harmful effect of voltage drop during switch operation. This preliminary protective action prevents the burnout condition from developing.
Data Source
AI summary
Disclosed is a voltage protection circuit for preventing power amplifier burnout in an electronic device. The electronic device includes a power amplifier (PA) configured to amplify a transmission signal, a switch configured to set a path of a signal outputted from the PA, a bias control circuit configured to control the supply of a bias current driving the PA, and a voltage protection circuit configured to provide a main control signal for turning off the PA earlier than turning off the switch based on a battery voltage providing a driving power of the electronic device, and forward the main control signal to the bias control circuit, wherein, in response to receiving the main control signal instructing to turn off the PA from the voltage protection circuit, the bias control unit stops the supply of the bias current driving the PA.