DIO70040

Version 1.3, Aug 2025

www.dioo.com

© 2025 Dioo Microcircuits Co., Ltd. Jiangsu

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9. Application Information

Important notice: Validation and testing are the most reliable ways to confirm system functionality. The

application information is not part of the specification and is for reference purposes only.

9.1. Power supply considerations

A 10 μF ceramic capacitor from VIN to GND to prevent the input voltage from dropping during the hot-plug

condition is strongly recommended. However higher capacitance could help reduce the voltage drop. Further

more, bypassing the output with a 10 μF ceramic capacitor improves the immunity of the device to short-circuit

transients, because an output short will cause ringing on the input without the input capacitor. It could destroy

the internal circuitry when the input transient voltage exceeds the absolute maximum supply voltage even for a

short duration.

9.2. Undervoltage lockout

The undervoltage lockout (UVLO) circuit disables the power switch until the input voltage reaches the UVLO

turn-on threshold. Built-in hysteresis prevents unwanted on / off cycling due to input voltage drop from large

current surges.

9.3. Enable

The logic enable controls the power switch, driver, and other circuitry to reduce the supply current. The EN / EN

control pin must be driven to a logic high or logic low for a clearly defined signal input. Floating these control

lines may cause unpredictable operation.

9.4. Overcurrent protection

The DIO70040 responds to over current conditions by limiting output current to the ILIM levels. When an over

current condition is detected, the device maintains a constant output current and reduces the output voltage

accordingly. Complete shut down occurs only if the fault is present long enough to activate thermal limit.

Three possible overload conditions can occur. In the first condition, the output has been shorted to GND before

the device is enabled or before VIN has been applied. The DIO70040 senses the short circuit and immediately

clamps output current to a certain safe level.

In the second condition, an excessive load occurs while the device is enabled. When the excessive load occurs,

very high currents may flow for a short time before the current limit circuit can react. After the current limit circuit

has tripped (reached the overcurrent trip threshold) the device switches into constant current mode to limit the

current close to ILIM.

In the third condition the load is gradually increasing beyond the recommended operating current. The current is

permitted to rise until the current limit threshold (ILIM) is reached or until the thermal limit of the device is

exceeded. The DIO70040 is capable of delivering current up to the current limit threshold (ILIM) without damaging

the device. Once the threshold has been reached, the device switches into its constant current mode.