STR-A6000MZ datasheet(11/26 Pages) SANKEN

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STR-A6000MZ/HZ Series

STR-A6000MZ/HZ - DS Rev.1.2

SANKEN ELECTRIC CO.,LTD.

Mar.13, 2015

Operational Description

 All of the parameter values used in these descriptions

are typical values, unless they are specified as

minimum or maximum.

 With regard to current direction, "+" indicates sink

current (toward the IC) and "–" indicates source

current (from the IC).

9.1

Startup Operation

Figure 9-1 shows the circuit around the IC.

The IC incorporates the startup circuit. The circuit is

connected to the D/ST pin. When the D/ST pin voltage

reaches

Startup

Circuit

Operation

Voltage,

VST(ON) = 47 V, the startup circuit starts operation.

During the startup process, the constant current,

ICC(ST) = − 2.5 mA, charges C2 at the VCC pin. When the

VCC pin voltage increases to VCC(ON) = 15.0 V, the

control circuit starts operation. During the IC operation,

the voltage rectified the auxiliary winding voltage, VD, of

Figure 9-1 becomes a power source to the VCC pin.

After switching operation begins, the startup circuit turns

off automatically so that its current consumption

becomes zero.

The approximate value of auxiliary winding voltage is

about 15 V to 20 V, taking account of the winding turns

of D winding so that VCC pin voltage becomes Equation

(1) within the specification of input and output voltage

variation of power supply.

(min

(max

)

OVP

(

)

BIAS

(



⇒10.5 (V)



27.0 (V)

(1)

The oscillation start timing of the IC depends on

Brown-In / Brown-Out Function (refer to Section 9.9).

9.1.1 Without Brown-In / Brown-Out

Function (BR pin voltage is

VBR(DIS) = 0.6 V or less)

When VCC pin voltage increases to VCC(ON), the IC

starts switching operation, As shown in Figure 9-2.

The startup time of the IC is determined by C2

capacitor value. The approximate startup time tSTART

(shown in Figure 9-2) is calculated as follows:

)

(

)

INT

(

)

(

START

－



(2)

where,

tSTART

: Startup time of the IC (s)

VCC(INT) : Initial voltage on the VCC pin (V)

9.1.2 With Brown-In / Brown-Out Function

When BR pin voltage is more than VBR(DIS) = 0.6 V

and less than VBR(IN) = 5.60 V, the Bias Assist Function

(refer to Section 9.3) is disabled. Thus, VCC pin voltage

repeats increasing to VCC(ON) and decreasing to VCC(OFF)

(shown in Figure 9-3). When the BR pin voltage

becomes VBR(IN) or more, the IC starts switching

operation.

VAC

BR1

VCC

GND

D/ST

7, 8

Figure 9-1 VCC pin peripheral circuit

(Without Brown-In / Brown-Out Function)

VCC(ON)

VCC pin

voltage

Drain current,

tSTART

Figure 9-2 Startup operation

(Without Brown-In / Brown-Out Function)

VCC(ON)

VCC pin

voltage

Drain current,

tSTART

BR pin

voltage

VBR(IN)

VCC(OFF)

Figure 9-3 Startup operation

(With Brown-In / Brown-Out Function)

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