# EE 241 Design Problem - PowerPoint PPT Presentation

1 / 17

EE 241 Design Problem. Paguio , Cindy Sandoval, Andrew Valdez, Rozelle. Specifications. Typical Lab Supply Single Output Flyback converter in DCM Vi = universal supply (85V to 264V) Io = 0 to 3A Vo = 2V to 20V. Block Diagram. Linear Regulator. Flyback Converter. Assumptions:

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.

### Download Presentation

EE 241 Design Problem

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

## EE 241 Design Problem

Paguio, Cindy

Sandoval, Andrew

Valdez, Rozelle

### Specifications

• Typical Lab Supply

• Single Output

• Flyback converter in DCM

• Vi = universal supply (85V to 264V)

• Io = 0 to 3A

• Vo = 2V to 20V

### Flyback Converter

• Assumptions:

• Efficiency = 80%

• fs = 175kHz

• Iout = 5A

• Design Approach

• 5 Outputs (4.3V, 8.3V, 12.3V, 16.3V, 20.3V)

• Tap Configuration

• 15V Primary Auxiliary Output

• To power PWM Controller

• 24V Secondary Auxiliary Output

• To power op-amps in linear regulator and the flyback switcher

### Flyback Transformer Design

• Primary Side:

• Core: E14-3C90

• Ie = 78.6mm, Ae = 97.1mm^2, Ue =67

(1)

N = 26.68 turns

• Secondary Side:

(2)

15V flyback auxiliary output: Nsec = 3.48 turns

24V flyback auxiliary output: Nsec = 4.93 turns

### Flyback Transformer

• Secondary Side:

• Multi-output tap configuration

• Outputs are in 4V increments (4.3V, 8.3V, 12.3V, 16.3V, 20.3V)

• Eq. 2 is used to get Nsec for Vout = 4.3V

• Nsec(4.3V) = 0.998 turns

• Nsec(4V) = 0.938 turns

• Nsec(8.3V) = Nsec(4.3V) + Nsec(4V)

• Nsec(12.3V) = Nsec(4.3V) + 2*Nsec(4V)

• Nsec(16.3V) = Nsec(4.3V) + 3*Nsec(4V)

• Nsec(20.3V) = Nsec(4.3V) + 4*Nsec(4V)

### Flyback Transformer

• PWM Controller Circuit and Switch:

• Osc pin:

• fs = 175kHz, 1.8/RC, R >= 5kHz

• R1 = 5kohms, C4 = 2nF

• Sense pin:

• Pout = Vout,max*Iout,max = 20.3*5A=101.5W

• I_peak = (5.5*Pout)/Vin,min = (5.5*101.5)/(85*sqrt(2))

= 4.64A

• Rsense = 1.0/I_peak = 1.0/4.64 = 215mΩ

### Flyback (Simulation)

• Conditions: Vin = 85Vrms

### Flyback (Simulation)

• Conditions: Vin = 85Vrms