ADP1048ARQZ-R7 datasheet(16/84 Pages) AD

16 / 84 page

ADP1047/ADP1048

Data Sheet

Rev. 0 | Page 16 of 84

Figure 12 shows an example of the output voltage and the OVP

thresholds set. The rising and falling thresholds, FAST_OVP_

FAULT_RISE and FAST_OVP_FAULT_FALL, respectively, are

used for fast OVP protection. FAST_OVP_FAULT_RISE

corresponds to OVPUP, which is the trip point for overvoltage

protection (see Figure 13). FAST_OVP_FAULT_FALL corre-

sponds to OVPDOWN, which is the reset point for the fast OVP.

When the rising threshold is triggered, the programmed action

is applied and the threshold is switched to the programmed fall-

ing threshold (if the programmed falling threshold is different

from the rising threshold).

A blanking time is applied when the thresholds are switched to

avoid spurious signals (see the timing diagram in Figure 13). A

programmable debounce time is applied to the OVP signal as

well to avoid false triggering.

The rising and falling thresholds are programmable from 1 V

to 1.5 V (at the OVP pin) using Register 0xFE2F and Register

0xFE30, respectively.

Open-Loop Protection

Open-loop protection detects differences between the OVP and

VFB pins. Identical resistor dividers are applied to these pins;

therefore, if a voltage difference is present, it means that one or

more resistors in the dividers have the wrong values or are not

connected. In this case, it is usually recommended that the user

shut down the system to prevent damage.

The open-loop protection detects a difference in voltage in

excess of ~100 mV, which equates to approximately 6.6% of

the full-scale range.

A debounce time of 10 μs is added to avoid false triggering. If

filtering capacitors are applied to the OVP and VFB pins, care

must be taken to make sure that the time constant difference

does not exceed 10 μs.

ADC INPUT RANGE = 1.6V

VOUT_OV_FAULT_LIMIT = 450V (REG 0x40)

FAST OVP

PROGRAMMING

RANGE

1.6V

0.5V

1.0V

VOUT_COMMAND = 385V (REG 0x21)

VOUT_UV_FAULT_LIMIT = 200V (REG 0x44)

VOUT_OV_WARN_LIMIT = 420V (REG 0x42)

ADC

FULL

RANGE

FAST_OVP_FAULT_RISE = 435V (REG 0xFE2F)

FAST_OVP_FAULT_FALL = 400V (REG 0xFE30)

Figure 12. Output Voltage Levels

OVPUP

OVPDOWN

OUTPUT

VOLTAGE

OVP PIN

OVPFLAG

DEBOUNCE

TIME

10µs

Figure 13. OVP Thresholds and Timing

Table 7. Programmable Options for Open-Loop Protection (OLP)

Parameter

Values or Options

Comments

Debounce Time

10 μs (fixed)

Minimum duration of pulse to be considered

Propagation Delay

200 ns (fixed)

Does not include debounce

Actions for OLP

Immediate shutdown and wait for PSON;

disable PWM until the flag is cleared;

shut down and soft start; ignore (do nothing)

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