TEA1713T_11 NXP [NXP Semiconductors], TEA1713T_11 Datasheet - Page 26

• Manufacturer Part Number: TEA1713T_11
• Description: Resonant power supply control IC with PFC
• Manufacturer: NXP [NXP Semiconductors]

NXP Semiconductors
TEA1713T
Product data sheet
7.8.8.2 Soft start charge and discharge
V
V
C
soft start function is zero when V
V
minimum) and at a minimum (≈ 3 V). Below V
discharge current is reduced to a maximum-frequency soft start current of typically 5 μA
The voltage is clamped at a minimum of V
outside the operating area of V
disturbance during normal output voltage regulation, but ensure that overcurrent
regulation can respond quickly.
At initial start-up, the soft start capacitor C
frequency sweep from maximum to operating frequency. As well as being used to softly
start up the resonant converter, the soft start functionality is also used for regulation
purposes (such as overcurrent regulation). C
discharged. In the case of overcurrent regulation, a continuous alternation between
charging and discharging takes place. In this way V
overruling the signal from the feedback input.
The (dis-)charge current can have a high value, I
fast (dis-)charge, or it can have a low value I
(dis-)charge. This two-speed soft start sweep allows for a combination of a short start-up
time for the resonant converter and stable regulation loops (such as overcurrent
regulation).
Fig 15. Relation between SSHBC/EN voltage and frequency
RFMAX
fmax(SSHBC)
SSHBC/EN
ss(HBC)
The fast (dis-)charge speed is used for the upper frequency range where V
below V
converter do not react strongly to frequency variations.
and V
is charged, V
ss(hf-lf)(SSHBC)
is clamped at a maximum of V
(typ. 3.2 V), which corresponds to the maximum frequency. During start-up,
V
V
SSHBC/EN
fmax,ss(RFMAX)
fmax,fb(RFMAX)
All information provided in this document is subject to legal disclaimers.
V
RFMAX
SSHBC/EN
Rev. 2 — 9 February 2011
are of opposite polarity. At initial start-up, V
(typ. 5.6 V). In the upper frequency range, the currents in the
0
0
rises and the frequency decreases. The contribution of the
fmax(SSHBC)
V
I
I
SNSFB
fmin(SNSFB)
SSHBC/EN
pu(EN)
V
fmax(SSHBC)
< I
fmin(SNSFB)
< I
V
clamp(SSHBC)
ss(HBC)
is above V
pu(EN)
RFMAX
to V
SNSFB
Resonant power supply control IC with PFC
V
SSHBC
ss(lf)(SSHBC)
ss(HBC)
fmax(SSHBC)
fmin(SSHBC)
< I
(typ. 3 V). Both clamp levels are just
ss(hf)(SSHBC)
is charged to obtain a decreasing
fmax(SNSFB)
SSHBC/EN
can therefore be charged or
fmin(SSHBC)
f
(typ. 8.4 V) (frequency is at a
HB
(typ. 40 μA), resulting in a slow
. The margins avoid frequency
(maximum frequency), the
can be regulated, thereby
(typ. 160 μA), resulting in a
(typ. 7.9 V).
014aaa863
V
fmin(SSHBC)
V
SSHBC/EN
clamp(SSHBC)
TEA1713T
f
f
max
min
f
© NXP B.V. 2011. All rights reserved.
HB
is below
SSHBC/EN
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is