PN8370

13/F, Building C, Wangzhuang Technology Innovation Center, Longshan Road,New District, Wuxi

Tel: +86(510)85217718 http://www.chipown.com.cn

Rev.A.1507 8 / 10

FB

VINT

CC/CV

Control

PN8370

R1

R2

Vsense

Naux

Ns

Vaux

Vs

Is

Rw

Resr

Ic

Vout

Io

+ ΔV -

Figure 3 Icable

6. Reference Negative Temperature Compensation

As shown in Figure 3, the voltage of FB pin is

()

S

AUX

O

FB

N

R

R

N

R

K

V

V

K

V

×

+

×

=

Δ

+

=

)

2

1

(

2

,

（

5）

Where

V

△

has a negative temperature coefficient, K is a constant.

In PN8370, the voltage reference uses the negative temperature compensation technology. At room temperature, the

voltage reference is 2.5V. The voltage reference (VREF_CV) decreases while the temperature of chip increases. The

reference negative temperature compensation block compensates the

V, thus the output voltage keeps constant at full

△

range of temperature. The reference negative temperature compensation improves output precision.

7. Quasi-Resonant Switching

The PN8370 incorporates a unique proprietary quasi-resonant switching scheme that achieves valley-mode turn on for

every switching cycle in CV mode. This unique feature greatly reduces the switching loss. The actual switching

frequency can vary slightly cycle by cycle, providing the additional benefit of reducing EMI.

Figure 4 QR Mode

8. Protection Control

The PN8370 has several self-protection functions, such as Cycle-by-Cycle current limiting (OCP), Over-Voltage

Protection, Over-Temperature Protection, Feedback Loop open Protection, Output short circuit Protection, CS resistor

open/short circuit Protection and Under Voltage Lockout on VDD. All protections are self-recovered.