Application Hints

STV9325

6/14

4.1.1.1 Centering

4.1.1.2 Peak Current

From equation of peak current:

Finally, the bias voltage on pin 7 should be:

4.1.2

Ripple Rejection

When both ramp signal and bias are provided by the same driver IC, you can gain natural rejection

of any ripple caused by a voltage drop in the ground (see Figure 5), if you manage to apply the

same fraction of ripple voltage to both booster inputs. For that purpose, arrange an intermediate

Figure 5: Ripple Rejection

V

7

V

M

V

m

+

2

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

R

2

R

2

R

3

+

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

⎝⎠

⎜⎟

⎛⎞

×

=

I

P

V

M

V

m

–

()

2

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

R

2

R

1

xR

3

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

×

=

R

2

R

3

-------

2I

P

R

1

×

×

V

M

V

m

–

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

2

3

---

=

=

V

7

V

M

V

m

+

2

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

1

1

R

3

R

2

-------

+

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

×

7

2

----

1

2.5

--------

×

1.4V

=

=

=

Rd

Yoke

Ly

Power

Amplifier

Flyback

Generator

Thermal

Safety

7

32

5

6

1

4

+

-

Reference

Voltage

Ramp

Signal

Driver

Ground

Source of Ripple