ACT41000-101 datasheet(46/72 Pages) QORVO

46 / 72 page

ACT41000

Programmable Voltage, Programmable Current, Low Noise

RFPoL Step-Down Voltage Regulator

SW pin to the low state (high-side FET: OFF, low-side FET: ON) until the low-side FET current flow comes below the

IOCP(CBC,low) target. During this protection working, the gate driver logic circuits ignore signals from main regulation control

blocks.

A result of the cycle-by-cycle current limit protection looks like a CC operation. And also, continuous cycle-by-cycle

operation reports the device in a CC operation by setting the Reg03[4] bit to logic-H.

Unlike the Programmable Current Limit operation, this cycle-by-cycle current limit protection is outside of the device safe

operating area and the system should not operates the device in a continuous cycle-by-cycle current limit.

Over-Current Protection

The over-current protection is a superset of the Cycle-by-cycle Current Limit protection. When the Cycle-by-cycle Current

Limit block repeats four (4) consecutive pairs of IOCP(CBC,high) and IOCP(CBC,low) detections, the device triggers this over-

current protection.

The Reg02[6] bit is set logic-H to indicate this error.

See Executing Protections for the execution of this protection.

Practically, without any board level failure condition, the Cycle-by-cycle Current Limit protection reduces main inductor

current flow very effectively within one cycle before observing four times of events. So this over-current protection gets

triggered by an event of shorting the output, shorting the SW pin or shorting the coil.

Over-Voltage Protection

The over-voltage protection (OVP) monitors and maintains the output voltage at the FB_VO pin not to exceed the VOVP

threshold. For any reason, it exceeds the threshold, the main-buck triggers the over-voltage protection.

The Reg02[5] bit is set logic-H to indicate this error.

See Executing Protections for the execution of this protection.

Under-Voltage Protection

The under-voltage protection (UVP) monitors the output voltage at the FB_VO pin at the VUVP(CV) or the VUVP(CC) threshold.

See UVP selection. For any reason, it falls below the threshold, the device triggers the under-voltage protection.

The Reg02[4] bit is set logic-H to indicate this error.

See Hiccup Operation, Latch-off Operation and Executing Protections for the execution of this protection.

UVP selection

To support various application cases, the main-buck provides different UVP threshold options.

When using the CC block, the output voltage is expected to drop when transits from the CV to the CC operation. So the

UVP is expected to trigger at lower threshold target for the CC operation. The Reg0B[3] bit at logic-L selects VUVP(CC) for

this purpose. Setting this bit at logic-H selects VUVP(CV) for the CV operation.

In case a wide CC operation range is needed more than the VUVP(CC) target, the UVP can be disabled by setting the

Reg09[3] bit at logic-H. With this Reg09[3] bit, the CC block keeps its operation to the full range down to the VIT(CC,fall)

target.

By setting the Reg09[3] bit, the UVP protection "action" is disabled at the Control Logic block level regardless

of the FB_VO pin voltage. Still the status indicator bit Reg02[4] and its detector circuit is active and an

interrupt is generated when the FB_VO cross the threshold. The Reg07[4] mask bit helps this situation if an

interrupt is not needed.

By disabling the UVP by the Reg09[3] bit, there is no way to detect an event of output short. When a short

event happens without the UVP, there are only the Thermal Protection and the Over-Current Protection

blocks to protect the device and a risk of damaging the device increases.

Hiccup Operation

By setting the Reg09[2] bit at logic-L, the main-buck regulator repeats a "wait" and "retry" cycle, that is so called a "hiccup"

operation. At the first time the output voltage hits the UVP threshold, the device disables its switching operation for the

tW(HICCUP) of time period, and then the device restart the switching. If a cause of the under-voltage condition goes away

ACT41000 Data Sheet, Rev. B, 01-Apr-2022

Subject to change without notice

ACT41000-101 Datasheet(PDF) 46 Page - Qorvo, Inc

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