TEA1501T View Datasheet(PDF) - Philips Electronics
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TEA1501T Datasheet PDF : 21 Pages
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Philips Semiconductors
TEA1501
GreenChip SMPS controller IC
7.3.8 Gate driver
The gate driver switches the power switch. The power switch is turned on at the beginning
of every oscillator cycle and is turned off by the primary current comparator or by the
maximum on-time. The power switch is also prevented from turning on if VAUX has
reached its regulation level or in the case of active overtemperature protection or active
undervoltage lockout protection.
7.3.9 Power switch
The power switch is an integrated high voltage Lateral Diffused Metal Oxide
Semiconductor Transistor (LDMOST) with a Rdson of 40 Ω, a maximum peak drain voltage
of 650 V, a maximum continuous drain voltage of 500 V and a maximum drain current of
0.25 A.
7.3.10 Primary current comparator
The primary current comparator senses the voltage across the external sense resistor
RSOURCE which reflects the primary current. The detection level of the comparator is 0.5 V.
The power switch is switched off quickly when the source voltage exceeds this detection
level. The comparator has a typical propagation delay of 80 ns. If the dV/dt of the drain
voltage has to be limited for ElectroMagnetic Interference (EMI) reasons, a capacitor can
be connected between the DRAIN and SOURCE pins of the TEA1501. The discharge
current of this EMI capacitor does not flow through the sense resistor RSOURCE and does
not activate the comparator.
7.3.11 Leading edge blanking
To prevent the power switch from switching off due to the discharge current of the
capacitance on the DRAIN pin a Leading Edge Blanking (LEB) circuit has been
implemented. The leading edge blanking time is defined as the maximum duration time
needed to discharge the capacitance at the drain of the power switch. The leading edge
blanking time is determined by the reference resistor to obtain an accurate and
temperature independent time. The LEB time tracks with the period time of the switch
oscillator.
7.3.12 Modulator
The modulator determines the regulation level of VAUX. For a burst duty cycle from
0 % to 40 % the AUX voltage is regulated to 20 V. For stable operation in Burst mode a
decrease in regulation voltage is integrated for a burst duty cycle above 40 %. At 100 %
burst duty cycle the regulation voltage is 17.5 V.
TEA1501_2
Product data sheet
Rev. 02 — 31 March 2006
© Koninklijke Philips Electronics N.V. 2006. All rights reserved.
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