HT2802S

6/8

High performance primary sensing regulator (PSR)

www.hotchip.com.cn

Ver1.0

The secondary rectifier diode peak current is determinated by the peak current of

primary-side inductance which also affects the output current. The corresponding relation

between the primary peak current and the secondary peak current is as follows

Ipk

Ns

Np

Ipks





Ipk: primary peak current ; NP: primary winding turns; NS: secondary winding turns;

Ipks :secondary peak current

And primary inductance peak current is determinated by Pin 4 to RCS resistance, the

primary inductance peak current and RCS resistance are in inverse proportion, so only

need to adjust CS resistance to achieve different output currents. Output current Iout and

primary current are given by

Toffs

Tons

Tons

Ipks

2

1

Iout









Iout: Output current; Tons: secondary rectifier diode on-time; Toffs: secondary rectifier

diode off-time

OUTPUT CABLE COMPENSATION

HT2802S built-in output cable drop compensation circuit. When it outputs different

loads, the cable drop compensation circuit provides cable drop voltage compensation which

is in fixed proportion with output voltage. The internal circuit will generate one cable drop

compensation signal once have one 100nF capacitor connected with external Pin CPC

PROTECTIVE FUNCTIONS

In order to guarantee a safe and reliable circuit to all occasions, HT2802S built-in rich

protection circuits, such as OCP ,OVP, FB open-loop protection etc. as intergration. Once

abnormality, it will come into protection mode

TYPICAL APPLICATION CIRCUIT

+

-

C1

D1-D4

R2

R3

C3

D5

C2

D6

C4

VCC

CPC

GND

CS

FB

HV

R4

U1

HT2802S

R5

R6

C5

D7

R7

VO-

VO+

-

T1

100-

240Vac

R1

Typical application of HT2802S （Output：5V/2.0A）