STK391-020 查看數據表（PDF） - SANYO -> Panasonic

零件编号

产品描述 (功能)

比赛名单

STK391-020

2-Channel Convergence Correction Circuit (IC max = 6A)

SANYO -> Panasonic 

STK391-020

Maximum Ratings

Tj max, Tc max, θj-c

The heatsink design is determined by the maximum rat-

ings of several key parameters–Tj max, Tc max and θj-c.

• Tj max (junction temperature)

Tj max is dependent on the physical structure of each func-

tional element. A junction temperature exceeding this rat-

ing can lead to device deterioration and breakdown, so

the design must not exceed this rating.

• Tc max (operating substrate temperature)

Tc max is dependent on the materials used within an ele-

ment and on the circuit design, and should be selected on

the basis of reliability. Operation exceeding this value is

not guaranteed.

• θj-c (thermal resistance)

θj-c is dependent on the heatsink design, which can vary

greatly. the heatsink necessary is determined by calcula-

tion using the maximum rating for Tj.

As Tj and Tc operating conditions are independent, the

heatsink must be designed to satisfy the maximum ratings

for both parameters.

The power dissipation, Pd, is the sum of channel 1, Pd1,

and channel 2, Pd2, power dissipations.

Pd max=Pd1 max+Pd2 max

Therefore, form equation (1),

θc-a< Tc max – Ta max ................................ (3)

Pd max

the necessary heatsink resistance is determined (note that

Tc max=105°C)

The power dissipation per power transistor per channel, Pc,

is related to the transistor junction temperature by the fol-

lowing equation.

Tj=Pd max×θc-a+Ta+Pc×θj-c ............................ (4)

where Tj cannot exceed Tj max=105°C. Therfore, in order

to maintain Tj below 150°C, a lower heatsink thermal re-

sistance, θc-a, is necessary to lower Tc.

Heatsink Design Considerations

In the expressions below Pd represents the operating IC

substrate internal power dissipation and Pc represents the

power dissipation per transistor. The heatsink thermal re-

sistance, θc-a, required to dissipate the total power dissi-

pation, Pd, is determined as follows :

Condition 1: IC substrate temperature not to exceed 105°C

Pd×θc-a+Ta<105°C (Tc max) ............................ (1)

Where Ta is the guaranteed maximum ambient tempera-

ture.

Condition 2: Power transistor junction temperature, Tj, not

to exceed 150°C

Pd×θc-a+Pc×θj-c+Ta<150°C (Tj max) .............. (2)

Where θj-c is the power transistor thermal resistance per

transistor. Therefore, the heatsink design must satisfy both

these expression.

Design Process

A model circuit for a single channel in the STK319-020 is

shown below.

Heatsink Design Example

This example assumes the following worst-case conditions–

VCCH=±35V, VCCL=±25V, output coil LY=80µH and

RY=0Ω, current detector resistance RNF=4.7Ω, Ip-o

max=0.6Ap-o (Ip-o (Ip-p=1.2A) sawtooth wave input, Io

(DC) max=0.6A DC input, both chanels operating, Ta

max=60°C (guaranteed maximum).

The channel1 power dissipation, Pd1, is given from Fig-

ures 1 and 2.

• Pd1 max=7.0W (AC) with sawtooth wave input

• Pd1 max=13.2W (DC) with DC input

As Pd1 max (AC) < Pd1 max (DC), the power dissipation

is greater with DC input. Also, lokking at the output tran-

sistor dissipation, Pc,

• Pc=0.5Pd1 with sawtooth wave input

• Pc=Pd1 with DC input (one side transistor continuously

ON)

the power dissipation is also higher with DC input. Ac-

cordingly, the heatsink design example below assumes DC

input. The power dissipation in the predriver stage is ig-

nored.

As Pd1 max=Pd2 max+13.2W, Pd max (both channels) is

given by.

Pd max=Pd1 max+Pd2 max=26.4W

From equation (3) with Ta=60°C,

θc-a=

Tc max – Ta

Pd max

=

105–60

26.4

= ........ 1.70°C/W

For a 2mm aluminum heatsink with no surface coating, the

necessary surface area, S, is given from Figure 3.

S=780cm2 (28cm×28cm)

No.5169–4/6

Share Link: