TEA1501/N1 데이터 시트보기 (PDF) - Philips Electronics

부품명

상세내역

제조사

TEA1501/N1

Greeny; GreenChip™

Philips Electronics 

Philips Semiconductors

Greeny; GreenChip™

Preliminary specification

TEA1501

DESIGN EQUATIONS

Primary peak current

The primary peak current is determined by the sense

resistor RSrc and may be calculated as shown below:

RSrc = V---I--dp--e-r-i-tm-e---c-t

MINIMUM VALUE OF RSrc

The maximum drain current is 0.25 A, this results in a

minimum value for resistor RSrc of 2.0 Ω.

Switch oscillator

The maximum output power of the converter is a function

of the switching frequency, provided that the converter

operates in discontinuous conduction mode.

Pout(max) = η × 12-- × Lp × Iprim2 × fswitch

Where η is the efficiency, Lp is the primary inductance,

Iprim is the primary peak current and fswitch is the switching

frequency.

The switching frequency can be adjusted between

20 and 50 kHz by the reference resistor RRef:

fswitch = k----s--w---i-t--c--h--1--×-----R----R---e---f

RANGE OF RRef VALUES

The minimum value for resistor RRef is 24 kΩ, the

maximum value is 62 kΩ.

Leading edge blanking

The leading edge blanking time is determined by the

reference resistor RRef as shown below:

tLEB = tconstant + ( kLEB × RRef)

The leading edge blanking time consists of a constant time

and a time which tracks with the period time of the switch

oscillator

Burst oscillator

The power threshold for data transfer is determined by the

burst frequency, according to the following formula:

Pdata = η × 12-- × Lp × Iprim2 × fburst × Ndata

The power ratio between Pdata and Pout(max) is therefore:

P-----oP--u--d-t-(-a-m-t--aa---x--) = f--b---u--r--sf--st--w-×---i-t-Nc--h--d---a--t--a

The desired Pdata/Pout(max) ratio determines the burst

frequency. For example, when the desired Pdata/Pout(max)

ratio is 0.5 then the burst frequency has to be 450 Hz at

50 kHz switching frequency. The burst frequency can be

adjusted by the reference resistor RRef and the burst

capacitor CBt as shown below:

fburst = -k---b--u---r-s---t--×-----R--1---R---e--f---×-----C-----B--t

MINIMUM VALUE OF CBt

The minimum value for capacitor CBt is 3.3 nF.

handbook, halfpage

900

fburst

(Hz)

fswitch = 50 kHz

MGM827

450

fswitch = 20 kHz

180

0

0

0.5

1

Pdata/Pout(max)

Fig.8 fburst versus Pdata/Pout(max).

1998 Aug 19

10

Share Link: