Application information

HVLED007

16/33

DS12866 Rev 1

As to the dynamic properties of a HVLED007-based Hi-PF QR flyback converter, the ICS

circuit is essentially transparent: it only affects the DC gain of the feedback loop. This is

intuitive if one recalls that one of the basic assumptions was that the time constant

Assuming 100% efficiency and that the Hi-PF QR flyback converter powers one or more

downstream switching regulators that drive the LED strings, the control-to-output transfer

function is:

Equation 8

4.4

As previously mentioned, one fundamental assumption for proper operation of the novel

the ICS meets the constraints:

Equation 9

essentially a DC level in any given switching cycle; the right-hand inequality ensures that

this DC level is able to change quickly enough to closely follow the ideal reference given by

(Equation 6) and depicted in Figure 7.

7

Secondary rms current

8

Secondary DC current

9

Secondary AC current

10

Low-frequency secondary current

11

Low-frequency output voltage ripple

Eq. #

Parameter

Expression

64

9

 K

v

--------------

+

Isdc = Iout

64

9

K

v

-------------

+

 = 2 I

V

o pk

–

1

22

 f

line

 C

out

--------------------------------------- =

4

 f

-------------------------------

G s

 =

-------- 1

-------------= 1

2

----





2

Rs

------------ 1

-------------

T



 << R

