1Terms and Definitions
| DC. | Direct current |
| IC | Integrated circuit |
| LDO | Low dropout voltage regulator |
| LNA | Low-noise amplifier |
| RF. | Radio frequency |
| rssi. | Received signal strength indication/indicator |
2References
For related documents and software, please visit:
//www.xmece.com/products/greenpak。
Download our free GreenPAK™ Designer software [1] to open the .gp files [2] and view the proposed circuit design. Use the GreenPAK development tools [3] to freeze the design into your own customized IC in a matter of minutes. Dialog Semiconductor provides a complete library of application notes [4] featuring design examples as well as explanations of features and blocks within the Dialog IC.
- GreenPAK Designer Software, Software Download and User Guide, Dialog Semiconductor
- AN-CM-300 Using a Dialog GreenPAK™ for Automatic Amplifier Bias Control.gp, GreenPAK Design File, Dialog Semiconductor
- GreenPak开发工具，GreenPAK Development Tools Webpage, Dialog Semiconductor
- GreenPak应用笔记，GreenPAK Application Notes Webpage, Dialog Semiconductor
- SLG46582V, Datasheet, Dialog Semiconductor
Author: Jon Ogden, Field Sales Engineer, Cain-Forlaw Company
3介绍
对话框的可配置混合信号GreenPak IC是在需要可配置和灵活的控制电路时使用的理想产品。本应用笔记将使用GreenPak详细说明，以自动设置放大器偏置电路。
4.Background Concept
通常需要根据需要将放大器操作为低功率水平。这节省了功耗，减少了热量，增加可靠性等。由于无线电链路不足，可能需要更高的功率水平。开发用于处理他的电路可以复杂并且具有多个外部元件。使用对话框GreenPak IC，设计人员可以轻松使用单个组件来为放大器提供所需的电压和控制电路，并提供有用的报警和监控功能。
This app note assumes operation at 900 MHz and will use the following devices as examples:
- GreenPak：对话框SLG46582V [5]
- Amplifier: Mini-Circuits PHA-23LNB+
- LNA: Mini-Circuits TSY-13LNB+
- Digital Step Attenuator: Skyworks SKY12325-35-LF
- Detector Diode: Skyworks SMS3923-079LF
The GreenPAK control circuit will provide two bias voltages to the PHA-23LNB+ and control input signal attenuation to the amp depending on received signal conditions and will also optionally enable the TSY-13LNB+ LNA with Bypass. The schematic of the circuit is shown in Figure 1.
5 Detector Circuit
在这个例子中, a Schottky detector diode is used to measure the RF signal being received at the antenna of the radio. The diode used in this design is a Skyworks SMS3923-079LF. The circuit design is quite basic and could likely be improved upon. RF is rectified across the junction of the diode. Any remaining RF on the anode side of the diode is shunted to ground by the 120 pF capacitor. Any DC appearing on the cathode side of the diode will be shorted to ground by the 560 nH inductor. Resistor R3 in the schematic was not used in this example. The circuit as designed outputs about 110 mV DC with approximately 0 dB input. A picture of a crude implementation is shown in Figure 2.
Figure 2: Crude Implementation
该电路的输出送入GreenPak IC上的RSSI输入引脚。当RSSI引脚中的电压下降（在该示例中的50mV）时，GreenPak将调整放大器的偏置点并增加提供给放大器的功率以提高性能。当接收信号足够强时，将减少偏置点，从而节省功率。
对该电路进行的改进可以包括在二极管上使用向前偏置以改善电压输出。更好和更清晰的布局也会导致性能提高。另外，可以使用放大器来增加电压输出水平。
6 Power Amplifier
The PHA-23LN+ MMIC amplifier from Mini-Circuits was chosen because it has very good performance in both gain and output power at two voltage levels: 3 V and 5 V. At 3 V the amplifier biases at 72.4 mA of with ~ 20 dB of gain and P1dB ~ +19 dBm. At 5 V, the amplifier biases at 141.7 mA with ~ 21 dB of gain and P1dB ~ +24 dBm. In this design, the PHA-23LN+ amplifier will be biased at 3 V in low power mode and 5 V in high power mode. A regulated 5 V supply will be required.
7数字步衰减器
在这个例子中, a digital step attenuator is used to control the amount of RF power being delivered to the amplifier. This could be used in a real-world circuit, or a microprocessor could be used to control the output of an RF chipset. The Skyworks SKY12325-350LF is a 3-bit, 7 dB digital step attenuator. When all 3 bits are at logic low, the attenuator is at maximum attenuation. At logic high, the attenuator is at minimum attenuation.
8个低噪声放大器
The TSY-13LNB+ from Mini-Circuits is an LNA with bypass and extremely low current consumption. At 2.7 V bias, the amplifier has about 1.4 dB NF, 14 dB gain with about 7.7 mA current consumption. When the bias is removed, the bypass feature of the amplifier is enabled with minimal insertion loss (about -1.8 dB). The GreenPAK bias controller IC has an LNA enable pin that allows a microprocessor or other control device to enable the LNA switching feature if so desired. If this is not enabled, the LNA will always be turned off and in bypass mode.
9 SLG46582V GreenPak原理图
Internally, the schematic of the SLG46582V is shown in Figure 3. The explanation of the circuit functions will follow.
10 IC电路特性
Voltage Monitoring: The supply voltage to the IC must be greater than 4 V in order for the circuit to switch power states. This feature was implemented so that battery powered designs will conserve remaining battery power if the battery voltage begins to drop.
Temperature Monitoring: The SLG46852 features an on-board temperature sensor. If the temperature of the devices exceeds approximately 95 °C, the entire circuit will be turned completely off. Once the IC die cools sufficiently, the temperature fault will clear and the LDOs will be re-enabled at their proper operating state. Pin 3 of the SLG46582 has been configured to allow monitoring of the temperature fault state. This pin will be set high if a fault has occurred.
短路保护：SLG46582中的调节器具有短路/过电流传感功能。如果调节器的输出电流升高到420 mA以上，或者输出电压下降到40 mA的0.5 V以下，则设定故障条件，并且调节器将完全关闭。对于LDO0，通过电流信号直接送到调节器的使能销。对于LDO1，该信号被绑定到3位和门3-L1。IC的引脚1将反映LDO的LDO故障状态。在正常操作期间，当发生故障时，它将很低。
11Operation
Comparator0 monitors the voltage from the receive signal detector circuit on pin 2. If this voltage falls below 50 mV (this voltage can be set at design time to whatever value is appropriate based on the detector design and performance requirements), then Comparator 0 is driven to a low output. Following the comparator is a 500 millisecond delay block that will hold the line high unless the fade that caused the detector voltage drop is longer than 1/2 a second. This comparator signal is then fed into a lookup table that will output high if the supply voltage is greater than 4 V. Once the lookup table is driven high, it changes the operation of LDO0 from that of a 3 V regulator to that of a power switch which will supply the full 5 V to the PHA-23LN+. Pin 10 will also go high which can be used by the exciter circuit as a flag to increase power. Pin 19 will be set to high to control the digital step attenuator. Additionally, if Pin 6 (LNA Enable) is driven high, LDO1 will be enabled thus powering and enabling the TSY-13LNB+. Once the fade condition has passed and the detector voltage is sufficiently high, then Comparator0 goes high. The output of the 3-bit lookup table will drive low. LDO0 will be turned back to LDO mode at 3.5 V output and LOD1 will be turned off which will cause the TSY-13LNB+ to go into bypass mode. Three millisecond delay blocks have been added to the control lines for each LDO. In the case where the LNA is enabled, switching the operational state of both LDOs at the same time causes an issue where LDO0 does not regulate properly when switching from Power-Switch mode to regulator mode. The delay blocks ensure that LDO1 is always enabled and disabled while LDO0 is in PowerSwitch mode.
12Pin Descriptions
Pin 1: LDO Fault monitor. Will be low in normal operation. Will be high if either LDO has a fault. The LDO with a fault will be disabled until the fault condition is cleared.
Pin 2: RSSI Voltage Input from detector circuit
引脚3：通过温度监测器 - 如果IC管芯温度超过95℃，则在正常操作中较低。如果管芯温度超过95°C，则在温度下降之前，两个LDO将完全禁用。
Pin 4: Manual high power assert. Pulling this pin low will set the output of the 3 bit lookup table high, turning on the LNA (if enabled) and setting LDO0 to Power Switch mode and setting pins 10 and 19 high.
Pin 5: Voltage monitor input. It monitors the 5 V input line and if it drops below 4 V, Comparator 1 is driven low resulting in high power mode being disabled. This is designed to save battery power in a battery operated circuit.
Pin 6: LNA Enable. If this pin is set high, the LNA will be enabled during high power operations.
引脚7：VDD - 该引脚应设置为电源电压 - 5 V（注意：SLG46582最大VDD为6 V）。
Pin 8 and Pin 9: SCL and SDA pins respectively for the I2C interface. Any of the IC's functions can be accessed via I2C. Additionally, any function can be reprogrammed during operation (for example, a different RSSI threshold could be set). Any reprogramming will revert to the default values when the IC is power cycled.
引脚10：HP已启用 - 如果启用了高功率模式并且没有温度故障，并且没有LDO故障，则该引脚将设置为高电平。
Pin 11, 13: LDO0 output. Connected to the PHA-23LN+
Pin 12: LDO0 Input - This should be set to the 5 V Vdd line
Pin 14, 16: LDO1 output. Connected to the TSY-13LNB+
Pin 15: LDO1 Input - This should be set to the 5 V Vdd line
Pin 17: Ground
引脚18：LNA启用/旁路 - 如果启用并运行并且没有温度或LDO故障，请设置为高电平。如果禁用LNA并以旁路模式设置为低电平
引脚19：DSA控制：在高功率模式下设置为高，在正常操作模式下设置为低电平
Pin 20: Ground
The SLG46582V enables the designer complete control over their bias circuit and uses a minimum number of external components. This saves the designer both board space and cost.
The BOM for the circuit is shown in Table 1 along with manufacturer part numbers and Digi-Key part numbers (where available).
Table 1: The BOM for the Circuit
RefDes |
Value |
Manufacturer |
Manufacturer Part Number |
Digi-Key Part Number |
Quantity |
|---|---|---|---|---|---|
C1，C2，C3，C4 |
4.。2μF |
Samsung Electro-Mechanics |
CL05A425KO5LUN C |
1276-CL05A425KO5 |
4. |
C10., C15 |
.001μF. |
Johanson Dielectrics Inc. |
500R07W102KV4T |
709-1133-1-ND |
2 |
C18 |
.01μF |
Johanson Dielectrics Inc. |
500R07W103KV4T |
709-1134-6-ND |
1 |
C19 |
1.2 PF. |
Johanson Technology Inc. |
500R07S1R2AV4T |
712-1609-6-ND |
1 |
C20 |
120 pF |
Johanson Technology Inc. |
501S42E121JV4E |
712-1523-2-ND |
1 |
C5, C6, C7, C8, C9, C11, C12, C13, C14, C17 |
0.1 μF |
Johanson Dielectrics Inc. |
160r07x104kv4t. |
709-1129-1-nd. |
10. |
D1 |
SMS |
Skyworks Solutions Inc. |
SMS3923-079LF |
863-1695-6-ND |
1 |
L1 |
3 nH |
Johanson Technology Inc. |
L-07C3N0SV6T |
712-1457-6-ND |
1 |
L2 |
1uH |
Johanson Technology Inc. |
L-15F1R0JV4E |
L-15F1R0JV4END |
1 |
L3 |
1nH |
Johanson Technology Inc. |
L-07W1N0CV4T |
L-07W1N0CV4 T-ND |
1 |
L4 |
0.68μH. |
Johanson Technology Inc. |
L-15FR68JV4E |
L-15FR68JV4END. |
1 |
L5 |
560 NH. |
Johanson Technology Inc. |
L-15FR56JV4E |
L-15FR56JV4END |
1 |
R1. |
4.32 Ohm |
KOA Speer Electronics, Inc. (VA) |
RK73H1ETTP4320F |
2019- |
1 |
R2. |
1。21KOhm |
KOA Speer Electronics, Inc. (VA) |
RK73H1ETTP1211F |
2019- |
1 |
R3. |
Do Not Place |
- |
1 |
||
U1. |
SLG46852 |
yabo国际娱乐 |
SLG46582V |
1 |
|
U2. |
SKY12325-350LF |
Skyworks Solutions Inc. |
SKY12325-350LF |
863-1258-1-ND |
1 |
U3. |
TSY-13LBN+ |
迷你电路 |
TSY-13LNB+ |
1 |
|
U4. |
PHA-23LN+ |
迷你电路 |
PHA-23LN+ |
1 |
Note: Values were copied from the Mini-Circuits data sheets for both amplifiers.
13 Raspberry Pi Control Software
A RaspberryPi software package has been written to allow monitor and control of the SLG46582 circuit described in this app note. The software allows the RaspberryPi’s GPIO pins to interconnect with the SLG46582V. The HighPower Assert and LNA Enable functions on pins 4 and 6 have been implemented. The High Power Enabled (Pin 10), LNA Enabled (Pin 18), LDO Fault (Pin1) and Overtemp (Pin 3) flags are all monitored. This software requires the WiringPi Libraries for proper operation. Please seehttp://wiringpi.comfor installation instructions.
RaspBerryPI的GPIO引脚显示在下面的图4中。
对于我们的电路，Wiringpi引脚0（GPIO17）是HP_ENABLE引脚。Wiringpi引脚2（GPIO27）是LNA_ENable销。对于监控侧，WIRINPI引脚4（GPIO23）是HP_ENABLED标志。Wiringpi引脚5（GPIO24）是LNA_ENABLED标志。Wiringpi引脚6（GPIO25）是过度标志。Wiringpi引脚27（GPIO16）是LDO_Fault标志。
14.Measurements
要使用Mini-Circuits江源发展促进会进行测量4.000HP as the signal generator (Figure 5). Power measurements were made using Mini-Circuits PWR-SEN-8GHS USB power meters. Attenuation control to simulate signal fading was made using a Mini-Circuits RCDAT-6000-90. The signal generator was set to 900 MHz and the output power to +2 dBm. Following the output of the signal generator, the RF path was split using a Mini-Circuits ZX10-2-252-S+ power splitter. One arm of the power splitter attached to the SKY12325-350LF DSA. The other arm of the power splitter was connected to the RCDAT controllable attenuator. This arm was then connected to the TSY-13LNB+ LNA. The output of the TSY-13LNB+ was connected to another Mini-Circuits PWN-SEN-8GHS power sensor. A GreenPAK Advanced evaluation board and SLG46582-DIP module were used for the bias controller emulation. A Klein Tools DVM was inserted into the supply line for the PHA-23LN+ to measure the bias current. Each RF path was measured without the circuit in place and offsets entered into the power meters to set the reference to 0 dBm. This allows us to see the gain of the RF circuits. The setup is shown in Figure 6.
Figure 5: Signal Generator Setup
RaspBerryPI控制器的布线如下图7所示。
Figure 7: The Wiring from the RaspberryPi Controller
In low power mode, the PHA-23LN+ drew 65.7 mA at 3.0 V. This is slightly lower than the data sheet specification of 72.4 mA. At 5 V bias, the PHA-23LN+ drew 131.4 mA. The spec calls out 141.7 mA (see Figure 8).
In low power mode the PHA-23LN+ output 12.24 dBm of power. The digital step attenuator has approximately 7 dB of attenuation. Since our input power is normalized to 0 dBm, this gives us approximately 19.24 dB gain. The spec sheet calls out 19.7 dB of gain at 3 V. This is close for what is really an uncalibrated setup. The LNA path is showing almost 3 dB of loss. The spec for the TSY-13LNB+ in bypass mode is about 1.9 dB of loss (see Figure 9). The approximately 1 db remaining loss is due to the detector circuit (as mentioned before it is not an ideal design).
Figure 9: Attenuation Measurement (0.00 dB)
In high power mode, the PHA-23LN+ output +20.28 dBm of power. The attenuator has approximately 0.8 dB of attenuation at minimum attenuation. This equates to 21.08 dB of gain. The spec at 5 V is 21 dB. The relative improvement in signal from low power to high power, we see an improvement of 8 dB of power with at 5 V. This makes sense since the attenuator has approximately 7 dB of attenuation at low power and the PHA-23LN+ has an extra dB of gain at 5 V vs. 3 V.
These first example image shows the performance with the LNA disabled. This is the point at which the high-power mode of the circuit became enabled. 11 dB of additional attenuation has been added to the LNA path dropping the detector voltage (see Figure 10).
通过启用LNA，我们会在高功率下看到以下性能。LNA提供约14.98dB的增益。这略高于典型的规格性能编号（参见图11）。
Decreasing the attenuation, the circuit shifts back to lower power mode around the 6 dB mark. There is approximately 5 dB of hysteresis in the RF power range. This has to do with the performance characteristics of the comparators in the GreenPAK IC. See Figure 12 on GreenPAK performance.
Figure 12: Attenuation Measurement (6.00 dB)
Next, as shown in Figure 13, it was desired to test the temperature monitoring performance of the SLG46582 bias controller. For this example, the Comparator3 trip level was changed from 1000 mV to 1050 mV. This equates to a temperature of about 85 °C vs 95 °C. This was done to prevent damage to the circuits but show how this safety feature performs. A heat gun was used to heat up the circuitry. As can be seen, the Temp Fault flag shows red. The DC voltage to the amplifiers was completely cut off until the circuit cooled. Once cooled, operations resumed as normal.
Figure 13: Attenuation Measurement (0.00 dB, 1050 mV)
15进一步的设计考虑因素
GreenPAK比较器:在衰减测试,it was discovered that the outputs of comparators in the GreenPAK devices do not instantly switch output states (high to low or low to high) upon hitting the threshold voltage. Rather, the output voltage from the comparator begins to drop at threshold and continues dropping linearly as the input voltage continues to drop below the reference voltage. It appears the gain and loop bandwidth of the comparators are not sufficiently high to switch right at threshold or shortly lower. The same holds true as the input voltage begins to increase and rise toward the reference voltage. Using an external Vref with precision resistors to set the voltage may improve this performance. That was not done in this example. Additionally, there are no additional pins available to use external references.
探测器设计：如前所述，探测器电路的设计可以在灵敏度，损失和整体性能方面提高。这种设计足以显示电路的性能。
Test Equipment: The Mini-Circuits portable test equipment pieces are excellent and low cost. However, should precise measurements need to be made including possible spectral degradation at the bias cross-over point, higher performance test equipment would be needed. At this time, it is unknown what performance impact would take place with the RF signal at the transition point between bias settings. This could be explored further in depth and we welcome any feedback on this.
Higher Power RF Amplifiers: If a similar circuit is desired for amplifiers that run with higher bias current than the SLG46582 is able to provide, a similar design has been done utilizing the Dialog SLG46867V GreenPAK IC. This GreenPAK has dual 2 A Power FET switches. The circuit switches between the two power FETs to change the bias point of the amplifier. The user would need to provide their own regulated voltages for each bias state (up to 6 V max). Please contact the author if this circuit is desired.