TEA19161CT datasheet(6/44 Pages) NXP

6 / 44 page

NXP Semiconductors

TEA19161CT

Digital controller for high-efficiency resonant power supply

TEA19161CT

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Product data sheet

Rev. 2 — 26 February 2020

6 / 44

Initially, when the voltage on the SUPIC pin is below the reset level VrstSUPIC) (3.5 V),

the SUPIC charge current is internally limited to Ilim(SUPHV) (0.75 mA). In this way, the

dissipation is limited when SUPIC is shorted to ground. When the voltage on the SUPIC

pin exceeds Vrst(SUPIC), the internal switch is closed.

To limit the IC power dissipation, an external resistor (RSUPHV) is required to reduce the

voltage drop between the SUPHV and SUPIC pins when charging the SUPIC capacitor.

RSUPHV must be dimensioned such that the maximum current is limited to below limiting

value ISUPHV (20 mA) and it can handle the required power dissipation. The maximum

power dissipation of the external resistor can be reduced by using several resistors in

series.

When the SUPIC reaches the Vstart(SUPIC) level (19.1 V), it is continuously regulated

to this start level with a hysteresis (Vstart(hys)(SUPIC); −0.7 V). It activates the switch

between the SUPHV and SUPIC pins when the SUPIC voltage drops to below

Vstart(SUPIC) + Vstart(hys)(SUPIC). It deactivates the switch when it exceeds Vstart(SUPIC).

When start-up is complete and the LLC controller is operating, the LLC transformer

auxiliary winding supplies the SUPIC pin. In this operational state, the HV start-up source

is disabled (see Figure 4).

When the system enters the protection mode, the SUPIC pin is also regulated to the

start level. During the non-switching period of the burst mode, the system also activates

the switch between the SUPHV and SUPIC pins when the SUPIC voltage drops below

Vlow(SUPIC). It regulates the voltage with a hysteresis of Vhys(low)SUPIC. In this way, the

system avoids that the SUPIC undervoltage protection (Vuvp(SUPIC)) is triggered because

of a long non-switching period in burst mode.

TEA19161CT Datasheet(PDF) 6 Page - NXP Semiconductors