CS1601

DS931PP6

13

5.11 Overpower Protection

The CS1601 incorporates an internal Overpower Protection

(OPP) algorithm. This provides protection from overload

conditions. This algorithm uses the condition that output

power is a function of the boost inductor (Section 5.4).

maintaining rated power and PFC. Further increasing the load

(~360V). Below this threshold, the circuit changes its

operating mode to startup with more power available to raise

canceled and power is now limited to the rated value. If the

overload is still present, this cycle will repeat.

If a sustained overload, or a repeated cycle of overload events

is detected for greater than 112 mS, the CS1601 shuts down

for 2.5 seconds, then attempts to restart.

5.12 Open/Short Loop Protection

GND), the measured output voltage decreases at a slew rate of

about 2 V/

s, which is determined by the ADC sampling rate.

The IC stops the gate drive when the measured output voltage is

lower than the measured line voltage. The IC resumes gate drive

switching when the current into the IFB pin becomes larger than

the current reference signal supplied to the IC on pin IAC falls to

zero.

5.13 Internal Overtemperature Protection

An internal thermal sensor triggers a shutdown when the

temperature exceeds 135°C (nominal) on the silicon. The

sensor sends a signal to the core that supplies current to all

internal digital logic, cutting off power from them. Once the

temperature of the IC has dropped by 9°C (nominal), the

sensor resets, allowing power to the logic.

5.14 Standby (STBY) Function

The standby (STBY) pin provides a means by which an

external signal can cause the CS1601 to enter a non-

operating, low-power state. The STBY input is intended to be

driven by an open-collector/open-drain device. Internal to the

shown in Figure 23. Since the pull-up resistor has a high

impedance, the user may need to provide a filter capacitor (up

to 1000pF) on this pin.

Figure 23. STBY Pin Connection

When the STBY pin is not used, it is recommended that the pin

<1 nF

600k

See Text

VDD

STBY

GND

CS1601

8

6

2