Features

The complete interface between LNBS and I2C bus

The built-in DC-DC converter used for single 12 V power

operation and high efficiency (typical typical example . 93%@0.5 An)

The output current limit that can be selected from the outside

The resistor

Compatible with the output of the main satellite receiver

voltage specification [ 123]

New accurate built -in 22 kHz audio generator

In line with the widely accepted standard (patent to be determined)

The startup of the fast oscillator helps Diseqc #8482; Code

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123] Built -in 22 kHz tuning detector, supports two -way Diseqc #8482; 2

Extremely low voltage drop adjustment regulator and high

Integrated power supply Pwm

] N-MOS allows low power loss

Two applications to bypass

output R-L filter and avoid sound distortion (R L filter according to Diseqc #8482; 2.0 specifications, see typical typical typical specifications . Application circuit)

Internal overload and ultra -temperature

Protection of I2C diagnostic position

output voltage and output current level

The diagnosis of I2C bit Feedback

LNB short-circuit dynamic protection

+/- 4 KV output power supply feet ESD tolerance

Instructions

used for simulation and digital dual-star receiving Instrument/satellite TV, satellite PC card,

lnbh24

is a single-chip regulator and interface IC. It is assembled in PowerSSO-36 Epad, especially the design to provide 13/18 V power and two independent. 22kHz audio signal antenna under LNB downstap and/or multi -switching box. In this application field, it provides a dual -tone set -top box with a very low number of components and a simple power consumption design. It uses I2C standard interface.

Introduction

LNBH24 includes two completely independent parts. In addition to the VCC and I2C input terminals, each circuit can be controlled separately and has an independent external component. For these two parts, the following specifications should be considered equally (A/B).

Application information

This integrated circuit has a built-in DC-DC boost converter, from a single 8 V power supply to 15 V power supply, generating a linear rear regulator to work at the minimum value Voltage (VUP) 0.375 W typical dispersion power. @500 ma load (Linear rear regulator pressure drops to internally keep in vup-vouT 0.75 V typical value). The underwriter lock circuit will reduce the entire circuit when the VCC provided to the fixed threshold (usually 6.7 V). Note: In this file, VOUT is used as a voltage output (VORX pin) on a linear rear regulator.

Disease Control #8482; Data Code

The new internal 22 kilo audio generator (being applying for a patent) is the factory according to the standard, which can select TTX bit (or or or through the I2C interface (or or TTX pin) and activated by dedicated pins (dsqin) can immediately perform Diseqc #8482; data coding, or if 22 kHz is requested in a continuous mode, 10 I2C bits are passed. In the standby state (EN position low). The TTX function must be disabled and the TTX is set to low.

Disease Control #8482; 2.0 Implementation

The built -in 22kHz tone detector completes a completely two -way Diseqc #8482; 2.0 (see :) Interface. Its input pin (Detin) must communicate with Diseqc #8482; buses, and extracted PWK data on the DSQOUT pin. Follow the two-way Diesqc #8482; 2 bus hardware requires an output R-L filter. LNBH24 is equipped with two output pins of each part, one for DC voltage output (VORX), and the other for 22 kHz audio transmission (VOTX). VOTX must only be activated during the audio transmission and VORX provides an output voltage of 13/18V. This allows 22 KHz tones to be consumed by R-L filter impedance (see Figure 4). In the 22 kg time transmission, in Diseqc #8482; 2.0 application, a DSQIN pin or 10 -bit activated VOTX pin must be set up by the TTX function. Both can control through the TTX pin and I2C bit. Once the audio transmission expires, VOTX must be disabled by setting the TTX to low to set the device to 22 kHz receiving mode. 13/18 V power supply is always provided to the LNB filter from the VORX pin.

Digital satellite equipment control #8482; 1.x Implementation

When LNBH24 is used for Diseqc #8482; 1.X always requires the correct application of R-L filter 22kHz audio generator. Operation (applying patent). See Figure 4). In this case, it is necessary to prevent the TTX function prevention before starting the 22 kHz data once the data transmission expires, transmitted and disabled. The tone can be activated with a DSQin pin or 10 I2C. The DSQIN internal circuit activates the 22 kHz tone on the VOTX output, and the delay from the TTL signal is 0.5 cycle ± 25 μSDSQIN pinsAfter the TTL signal is issued, it stopped expired with a delay of ± 25μs in 1 cycle.

Data coding is performed through an external audio generator (EXTM)

In order to improve the design flexibility, an external tone input pin (EXTM) can be used. This EXTM is a logical input pin, which uses the 22 kHz tone output LNBH24 integrated audio generator (similar to the DSQIN pin function) on the 22 kHz tone output on the VOTX pin. In fact, the output tone waveform characteristics are always used by the LNBH24 tone for internal control generators and EXTM signals to encode the VOTX output for regular control of DiseqC sound data. TTL compatible 22 kHz signal control EXTM pin function. Before sending the TTL signal on the EXTM pin, the VOTX audio generator must enable the high through the TTX function (TTX pin or TTX bit) in advance). Once the EXTM internal circuit detects the 22 KHz TTL signal code, it will activate the 22 kHz tone on the VOTX output. The delay from the TTL signal is 1.5 cycles ± 25 μs on the EXTM pin. The delay of ± 25μs per cycle stop expired (see Figure 2).

I2C interface

The main function of IC through the 8 -bit I2C bus on the system to control the register (SR 8 is in the writing mode) Essence There are 8 bits on the same register that can read the return (SR 8 digit in the read mode) to provide 8 diagnostic functions: 5 digits will report the diagnosis of five internal monitoring functions (Imon, VMON, TMON, OTF, OLF) Status, and Three will report the last output voltage register state (en, vsl, LLC) IC (see the diagnostic function part) received. Each part (A/B) has two optional I2C addresses to select the ADDR-A and ADDR-B pin (see the address pins feature table 10).

Output voltage selection

When the IC part is in the standby mode (EN is low), the power block is disabled. When the regulator block is activated (EN is high), the output logical control is 13 or 18 V, and is used to remotely control non -DiseqClnBS by remote control. In addition, LNBH24 is equipped with LLC I2C bit, which increases the selected voltage value to+1V to compensate for excessive voltage drops on the coaxial cable.

LNBH24 also meets the US LNB power standard. In order to allow the output voltage to quickly convert from 18V to 13V, vice versa, LNBH24 is equipped with a VCTRL TTL pin. When it is set to a low level and AT, its output is kept at 13 V set at high or floating. If necessary, VSEThe L and LLC bits must be set to high before switching the output voltage level with the VCTRL pin. If Vctrl 1 or floats, Vout 18.5 V (if LLC 1, then 19.5 V). Vctrl 0 il 13.4 伏 (LLC 0 or 1). It should be noted that when the voltage voltage, the VCTRL pin controls only the linear regulator VOUT -class VUP voltage only controls through the VSEL and LLC I2C bit. In other words, even if Vctrl 0 (keep vout 13.4 v) When VSEL 1 and 20.25 V, VUP 19.25 V typical values u200bu200bvsel LLC 1. This means that Vctrl 0 must be used in a short time to avoid higher power consumption. In the standby state (EN is low), all I2C and TTX pins must be set to low (if the TTX pin is not used, it can keep floating, but the TTX bit must be low at the standby state).

Diagnosis and protection function

LNBH24 has 5 diagnostic internal functions, and reads 5 ON system registers through the I2C bus (SR position in reading mode). All the diagnostic positions work normally (failure detected) and set to low. Two diagnostic sites are dedicated to overheating and overload protection status (OTF and OLF), and the remaining three are dedicated to the output voltage level (VMON), 22 KHz tone (TMON) and minimum load current diagnostic function (IMON).

Output voltage diagnosis

When VSEL 0 or 1 and LLC 0, the output voltage pin (VORX) is subject to internal monitoring, and as long as the output voltage level is lower than the guarantee limit, The vmon I2C bit is set to

""1"". The output voltage diagnosis is effective when LLC 0 and AUX 0. Any information of any vmonllc 1 and/or aux 1 must be ignored by the MCU.

22 kHz tone diagnosis

If the Detin pins are connected to the LNB output bus (see typical application circuits) through the decoupled capacitor. This TMON I2C bit provides a tone diagnosis function. If the 22 kHz tone amplitude and/or the sound adjustment rate exceeds the guarantee limit (see TMON limit features in the electrical system, see Table 13), the TMON I2C bit is set to ""1"".

Minimum output current diagnosis

In order to detect the lack of output load (not connected to the LNB connected to the bus or cable to IRD) LNBH24 is in the read mode by providing the minimum output current logo. If the output current is lower than 12 mAh, it is set to ""1"". Under normal circumstances, itest 1, 6 ma, and itest 0. The minimum current diagnosis function (Imun) is always active. In order to make it work normally even in multi -IRD configuration (multiple switches),In this configuration, the power current can only absorb the LNBH24 connection to the multi -switch box from a higher power supply voltage, with AUX I2C bit. Forced LNBH24 output voltage as the highest voltage on the bus (22 V typical values) on the bus. During the current diagnostic phase during the minimum value period, the AUX I2C bits can be set to high state before reading the Imon I2C bit. When the AUX bits are set to high, Vout is set to 22 V (typical values), and VUP is set to 22.75 v (vup vout+0.75 V typical values), which has nothing to do with the VSEL/LLC bit state. If the AUX function is used to force VOUT to 22 V, it is recommended to set the AUX bit to the low AS once the minimum current test phase is ends, the VOUT voltage will be controlled again according to the VSEL/LLC bit state again. In order to avoid error triggering the IMON function, it must be used only in the case of 22 kHz audio transmission (TEN 0 and dsqin LOW), otherwise the output current is lower than the minimum current threshold (6 mAh or 12 mAh).

Output current limit Selection

Linear regulator flow limit threshold can be set to the ISEL pin through the connected external resistor. The resistance value is limited by defining the output current through the following formula: IMAX (a) 10000/RSEL, RSEL is a resistor connected between ISEL and GND. The maximum selection of the current limit threshold is 1.0 a, RSEL 10 kΩ. The equal form above defines the threshold of each output. However, it is recommended not to avoid A+U trigger temperature protection from the two periods of A+U.

Overcurrent and short -circuit protection and diagnosis

In order to reduce the total power consumption in overload or short circuit, the device has dynamic short circuit protection. Can static (simple current clamp) or PCL bits of I2C SR. When the PCL (pulse current limit) bit is set to low, the dynamic work of overcurrent protection circuit: Once the overload is detected, the output is closed for a period of time, usually 900 milliseconds. At the same time, the OLF I2C system register is set to ""1"". After this period of time, the output will restore Ton (1/10) TOFF 90 milliseconds (typical values). At the end of the ton, if the overload is still detected, the protective circuit will cycle through TOFF and TON again. The overload was detected at the final tons, the normal operation was restored, and the OLF diagnostic level was reset to a low. The typical TON+TOFF time is 990 milliseconds, which are determined by internal timers. This dynamic operation can greatly reduce power consumption in short circuits, and can still ensure that in most cases. However, when the output may cause the launch difficulties in the high -capacity load, it is dynamically selected. This can be solved by starting any power in static mode (PCL 1), and then switched to the dynamic mode (PCL 0) after the selected time depends on the output capacitor. In static mode, diagnose OLF bit transferWhen reaching the current clamping limit, it is ""1"