The TPS563206 is an FCCM mode part. In this mode, the device has negative inductor current at light loading.

The device has NOC (negative overcurrent) protection to avoid too large negative current. NOC protection

detects the valley of inductor current. When the valley value of inductor current exceeds the NOC threshold, the

IC turns off the low side then turns on the high side. When NOC protection is triggered eight times continuously,

IC turns off both high side FET and low side FET. When the NOC condition is removed and output voltage

returns to target value, the device returns to normal switching.

Because the TPS563206 is a FCCM mode port, if the inductance is so small that the device trigger NOC, it

causes output voltage to be higher than target value. The minimum inductance is identified as Equation 2.

(2)

7.3.6 Enable Circuit

The EN pin controls the turn-on and turn-off of the device. When EN pin voltage is above the turn-on threshold,

the device starts switching and when the EN pin voltage falls below the turn-off threshold it stops switching. The

default status is low. Because there is a 1-uA pulldown current in internal IC.

EN can be controlled by a typical divider resister circuit from Vin or by a voltage of lower than 5.5 V.

TPS56320x also allows EN to connect to Vin by only a pullup resister, which is suggested a 100-k ohm resister.

EN voltage is clamped by a Zener diode. This Zener diode is not allowed to go through large current. R1 is not

allowed smaller than 80k ohm. R1 is also not suggested to use a too large resister to avoid EN not being able to

turn on. So R1 range is 80-k ohm to 3-M ohm. R1 is suggested to use 100-k ohm.

VIN

VIN

EN

GND

2V

Figure 7-1. EN Block Circuit

7.3.7 Undervoltage Lockout (UVLO) Protection

UVLO protection monitors the internal regulator voltage. When the voltage is lower than UVLO threshold voltage,

the device is shut off. This protection is non-latching.

7.3.8 Thermal Shutdown

The device monitors the temperature of itself. If the temperature exceeds the threshold value (typically 155°C),

the device is shut off. This is a non-latch protection.

7.4 Device Functional Modes

7.4.1 Eco-mode Operation

The TPS563203 operates in Eco-mode, which maintains high efficiency at light loading. As the output current

decreases from heavy load conditions, the inductor current is also reduced and eventually comes to a point

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TPS563203, TPS563206

SLUSEZ4 – MARCH 2023

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Product Folder Links: TPS563203 TPS563206