Rev. J 06/13

6

LNK302/304-306

www.powerint.com

Table 2.

Common Circuit Configurations Using LinkSwitch-TN. (continued on next page)

Topology

Basic Circuit Schematic

Key Features

High-Side

Buck –

Direct

Feedback

1. Output referenced to input

2. Positive output (V

3. Step down – V

4. Low cost direct feedback (±10% typ.)

5. Requires an output load to maintain regulation

High-Side

Buck –

Optocoupler

Feedback

1. Output referenced to input

2. Positive output (V

3. Step down – V

4. Optocoupler feedback

- Accuracy only limited by reference choice

- Low cost non-safety rated optocoupler

- No pre-load required

5. Minimum no-load consumption

Low-Side

Buck –

Optocoupler

Feedback

1. Output referenced to input

2. Negative output (V

3. Step down – V

4. Optocoupler feedback

- Accuracy only limited by reference choice

- Low cost non-safety rated optocoupler

- No pre-load required

- Ideal for driving LEDs

Low-Side

Buck –

Constant

Current LED

Driver

High-Side

Buck-Boost –

Direct

Feedback

1. Output referenced to input

2. Negative output (V

3. Step up/down – V

4. Low cost direct feedback (±10% typ.)

5. Fail-safe – output is not subjected to input

voltage if the internal power MOSFET fails

6. Ideal for driving LEDs – better accuracy and

temperature stability than Low-side Buck

constant current LED driver

7. Requires an output load to maintain regulation

High-Side

Buck-Boost –

Constant

Current LED

Driver

PI-3751-041509

+

+

FB

BP

S

D

LinkSwitch-TN

LinkSwitch-TN

PI-3752-041509

+

+

BP

FB

D

S

LinkSwitch-TN

PI-3753-041509

+

+

BP

FB

D

S

LinkSwitch-TN

PI-3754-041509

+

+

BP

FB

D

S

R =

PI-3755-041509

+

FB

BP

S

D

LinkSwitch-TN

300

Ω

2 k

Ω

2 V

100 nF

10

µF

50 V

PI-3779-041509

+

FB

BP

S

D

LinkSwitch-TN