CS1610A Ver la hoja de datos (PDF) - Cirrus Logic

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Fabricante

CS1610A

TRIAC Dimmable LED Driver IC

Cirrus Logic 

1. INTRODUCTION

CS1610A/11A

CS1612A/13A

BSTOUT 16

IAC 2

15k

Iref

MUX

ADC

15k

BSTAUX 1

VFB ZCD(th)

+

-

Boost ZCD

t B S TZCD

SOURCE 5

+

V S OURCE(th ) -

I S OURCE

SGND 4

IPK 8

VDD

eOTP 10

MUX

I CONNE CT

FBGAIN 9

V CONNE CT(th )

-

+

Voltage

Regulator

POR

+

-

V S T(th )

VS TP(th )

VZ

Blank

3

OLP

OCP

Peak

Control

DAC

-

+ VOLP (th)

+

- VOCP (th )

+

-

V P k_Max (th)

Output Open

t FB ZCD

Second Stage ZCD

+

- VOV P (th )

+

- VFB ZCD(th)

VDD

ICLA MP

14 VDD

13 GD

12 GND

11 FBSENSE

15 FBAUX

3 CLAMP

Figure 1. CS1610A/11A/12A/13A Block Diagram

A typical schematic using the CS1610A/11A for flyback

applications is shown on the previous page.

Startup current is provided from a patent-pending, external,

high-voltage source-follower network. In addition to providing

startup current, this unique topology is integral in providing

compatibility with digital dimmers by ensuring VDD power is

always available to the IC. During steady-state operation, an

auxiliary winding on the boost inductor back-biases the

source-follower circuit and provides steady-state operating

current to the IC to improve system efficiency.

The rectified input voltage is sensed as a current into pin IAC

and is used to control the adaptive dimmer compatibility

algorithm and extract the phase of the input voltage for output

dimming control. During steady-state operation, the external

high-voltage, source-follower circuit is source-switched in

critical conduction mode (CRM) to boost the input voltage.

This allows the boost stage to maintain good power factor,

provides dimmer compatibility, reduces bulk capacitor ripple

current, and provides a regulated input voltage to the second

stage.

The output voltage of the CRM boost is sensed by the current

into the boost output voltage sense pin BSTOUT. The quasi-

resonant second stage is implemented with peak-current

mode primary-side control, which eliminates the need for

additional components to provide feedback from the

secondary and reduces system cost and complexity.

Voltage across an external user-selected resistor is sensed

through pin FBSENSE to control the peak current through the

second stage inductor. Leading-edge and trailing-edge

blanking on pin FBSENSE prevents false triggering.

Pin FBAUX is used to sense the second stage inductor

demagnetization to ensure quasi-resonant switching of the

output stage.

When an external negative temperature coefficient (NTC)

thermistor is connected to the eOTP pin, the

CS1610A/11A/12A/13A monitors the system temperature,

allowing the controller to reduce the output current of the

system. If the temperature reaches a designated high set

point, the IC is shutdown and stops switching.

2

DS976PP4

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