NXP Semiconductors AN10907, Application Note

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AN10907 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2010. All rights reserved.
Application note Rev. 1 — 28 December 2010 36 of 82
NXP Semiconductors
AN10907
TEA1613T resonant power supply control IC
(13)
Example:
Given f
HB(min)
= 57 kHz
(14)
8.4.3.2 Maximum frequency setting for RFMAX
(15)
(16)
(17)
Analog to the situation with I
oscillator(min)
:
(18)
(19)
(20)
(21)
Example:
Requirement - f
HB(max)
= 180 kHz and CFMIN = 330 pF
(22)
(23)
Remark: Note that the average multiplication factor is 4.7. There is a small deviation in
value depending on other parameters and presetting conditions. Practical verification of
the result is advised.
CFMIN
I
oscillator min
 
2 2

f
HB min
 

V
oscillator
 
------------------------------------------------------------------------
150

A
8 f
HB min
 

---------------------------- = =
CFMIN
150

A
2 2

57 kHz

2

---------------------------------------------
0.00015
456000
------------------- 329 pF = = =
I
oscillator max
 
4.7
note
 
I
RFMAX max
 

I
oscillator min
 
+ =
I
RFMAX max
 
V
f max
 
RFMAX
--------------------- =
RFMAX
V
f max
 
I
RFMAX max
 
------------------------------
2.5 V
I
RFMAX max
 
------------------------------
= =
f
HB max
 
I
oscillator max
 
4 CFMIN

V
oscillator
 
---------------------------------------------------------------
4.7 I
RFMAX max
 
I
oscillator min
 
+

4 CFMIN

2

------------------------------------------------------------------------------------ = =
I
RFMAX max
 
8 CFMIN

f
HB max
 
I
oscillator min
 
–

4.7
------------------------------------------------------------------------------------------------ =
I
RFMAX max
 
8 CFMIN

f
HB max
 
150

A –

4.7
-------------------------------------------------------------------------------- =
RFMAX
2.5 V
I
RFMAX max
 
------------------------------
11.75 V
8 CFMIN

f
HB max
 
150

A –

-------------------------------------------------------------------------------- = =
I
RFMAX max
 
8 330 pF

180 kHz 150

A –

4.7
------------------------------------------------------------------------------
475

A 150

A –
 
4.7
------------------------------------------------ 69.15

A = = =
RFMAX
2.5 V
69.15

A
-----------------------
36 k

= =