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university:tools:lab_hw:adalm-sr1 [27 Jan 2020 11:47] – [FET and Current Sense Selection] Mihai Ionut Suciu | university:tools:lab_hw:adalm-sr1 [28 Feb 2022 01:38] – Joyce Velasco | ||
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====== ADALM-SR1 hardware ====== | ====== ADALM-SR1 hardware ====== | ||
+ | |||
===== Description===== | ===== Description===== | ||
- | The ADALM-SR1 (Analog Devices Active Learning Module, Switching Regulator | + | The Analog Devices Active Learning Module |
- | [[university: | + | |
- | The circuits required for these exercises exceed the complexity that can be constructed on a breadboard, so the ADALM-SR1 | + | Here is a short introduction video: |
+ | {{youtube> | ||
- | The Figure 1 shows an overview of the board, along with connections to an ADALM2000 (M2K) and meters. | + | We have started with several switching regulator exercises covering buck and boost regulators that can be used with the ADALM-SR1 board. |
+ | |||
+ | [[university: | ||
+ | [[university: | ||
+ | [[university: | ||
+ | |||
+ | |||
+ | |||
+ | The circuits required for these exercises exceed the complexity that can be constructed on a breadboard, so the ADALM-SR1 is required to run them. However, the simulations can be done beforehand to gain insight into the circuits' | ||
+ | |||
+ | The Figures 1a and 1b show an overview of the board along with connections to an ADALM2000 (m2k) and meters.\\ | ||
{{ : | {{ : | ||
- | {{ : | + | <WRAP centeralign> |
+ | {{ : | ||
- | <WRAP centeralign> | + | <WRAP centeralign> |
===== ADALM-SR1 Jumpers and Connections ===== | ===== ADALM-SR1 Jumpers and Connections ===== | ||
- | The ADALM-SR1 uses 0.635mm (0.025-mil) headers for configuration jumpers, signal inputs, and signal outputs. Signal inputs and outputs are 2-conductor headers with 5.08mm (200-mil) pitch so that they cannot be confused with configuration jumpers. The lower conductor is always a ground connection (that is not always used) and an arrow indicates whether the upper conductor is an input or output. | + | The ADALM-SR1 uses 0.635 mm (0.025-mil) headers for configuration jumpers, signal inputs, and signal outputs. Signal inputs and outputs are 2-conductor headers with 5.08 mm (200-mil) pitch so that they cannot be confused with configuration jumpers. The lower conductor is always a ground connection (that is not always used), and an arrow indicates whether the upper conductor is an input or output. |
- | (PLACEHOLDERS) | ||
- | The default jumper configurations for this board model are as follows: | ||
- | ^ Jumper ^Function | ||
- | |Px |Power Supply Select|Shunt installed across pins 2 & 3 (5V from Arduino) | | ||
- | |Py |Inductor Tap #|Shunt installed across pins 1 & 2 (6 taps/max inductance) | | ||
- | |Pz |Inductor Voltage |Open (for M2K connection) | | ||
- | |All Others ||Open / no shunt installed | | + | \\ |
+ | {{ : | ||
+ | <WRAP centeralign> | ||
+ | ==== Inductance Selection ==== | ||
+ | [[https:// | ||
\\ | \\ | ||
- | ==== Inductance Selection ==== | + | ^ ^ |
- | ^ ^ | + | ^ |
- | ^ | + | | **Position** | EXT IND |
- | | | + | | **Function** | Ext. inductor |
- | | | + | | ::: |
- | | ::: | + | |
+ | \\ | ||
+ | \\ | ||
- | ==== Topology | + | ==== Output Capacitors |
- | ^ ^ | + | A 4.7 μF capacitor is always connected to the output of the circuit. An additional 47 μF and 470 μF can be added by installing jumpers, as shown in the table below. |
- | ^ | + | |
- | | | + | |
- | | | + | |
- | | ::: | + | |
- | |||
- | ==== Output Capacitors Selection ==== | ||
^ ^ | ^ ^ | ||
^ | ^ | ||
| | | | ||
- | | | + | | |
- | | ::: | + | | ::: |
- | | ::: | + | | ::: |
- | ==== Feedback Selection ==== | + | \\ |
- | ^ ^ | + | \\ |
- | ^ | + | |
- | | | + | |
- | | | + | |
- | | ::: | + | |
==== Load Resistors Selection ==== | ==== Load Resistors Selection ==== | ||
+ | A resistive load may be connected to the output of the circuit. Resistances range from 12.5 Ω to 200 Ω and may be added in parallel, according to the table below. The jumpers are 3-position, with the right-hand position connecting the resistor to ground and the left-hand position allowing the effective resistance to be adjusted by Pulse-width-modulating the ground connection. | ||
+ | \\ | ||
^ ^ Load Resistors Selection | ^ ^ Load Resistors Selection | ||
^ | ^ | ||
| | | | ||
- | | | + | | |
- | | ::: | + | | ::: |
- | | ::: | + | | ::: |
- | | ::: | + | | ::: |
- | | ::: | + | | ::: |
- | | ::: | + | | ::: |
- | | ::: | + | | ::: |
- | | Notes | **7V max across 25Ω, 12.5Ω resistors will turn on the Over Power LED illuminates as warning.** | + | | Notes | **7 V max across 25Ω, 12.5Ω resistors will turn on the Over Power LED - which illuminates as a warning.** |
- | + | \\ | |
+ | The R87 (LOAD CONTROL) potentiometer controls the duty cycle of all load resistors whose jumper is placed in the adjustable position by switching the ground connection. (**YES** this is super weird, but it's convenient, and works much better than you'd think!) Duty cycle is guaranteed to be zero when fully counter-clockwise and 100% when fully clockwise. Thus, the load can be a combination of fixed and variable resistances and the exact duty cycle of the onboard PWM circuit can be measured at P40. The signal at P40 has a 1k impedance and may be overdriven by a 3.3 V logic signal, allowing the load to be stepped. | ||
+ | \\ | ||
+ | \\ | ||
+ | The load PWM frequency is fixed at 200 kHz, approximately 10x the typical operating frequency of most experiments, | ||
+ | \\ | ||
+ | \\ | ||
+ | A 0.1-ohm current sense resistor is in the ground return of the load resistors, allowing the total load current to be easily measured with the meter set to the 200 mV range at either the LOAD turret post (TP25) or the LOAD CURRENT jumper (P39). | ||
+ | \\ | ||
+ | \\ | ||
+ | ==== Topology, FET, and Current Sense Selection ==== | ||
+ | The selection between boost or buck topologies is made by jumpers P25, P35, and P37. | ||
+ | \\ | ||
+ | ^ ^ FET Selection | ||
+ | ^ | ||
+ | | | ||
+ | | | ||
+ | | ::: | ||
+ | | Notes | | ||
+ | \\ | ||
+ | In the boost configuration, | ||
+ | \\ | ||
+ | \\ | ||
+ | In the buck configuration, | ||
+ | \\ | ||
+ | <WRAP info> | ||
+ | Close inspection of the operation of the circuit will show that, in theory, either current sense amplifier will work for both topologies. Still, the amplifier that is NOT at the switch node is chosen to minimize errors due to common-mode excursion. | ||
+ | </ | ||
+ | \\ | ||
+ | \\ | ||
+ | ==== Mode Selection ==== | ||
+ | The ADALM-SR1 has several operational modes set by the jumpers, as noted below. | ||
+ | \\ | ||
+ | \\ | ||
+ | The MODE jumper selects between peak current mode and duty cycle control: | ||
+ | * Peak Current - a fixed frequency clock starts the inductor current ramp by turning on a MOSFET switch, and the switch opens when a peak current is reached. | ||
+ | * Duty Cycle - the duty cycle of the MOSFET switch is controlled directly. | ||
+ | \\ | ||
+ | ^ ^ | ||
+ | ^ | ||
+ | | | ||
+ | | | ||
+ | | ::: | ||
+ | | Notes | | ||
+ | \\ | ||
+ | <WRAP info> | ||
+ | The peak current circuit is always active even in duty-cycle mode, increasing robustness in the event of an output short circuit. | ||
+ | </ | ||
+ | \\ | ||
==== Duty Cycle Source Selection ==== | ==== Duty Cycle Source Selection ==== | ||
+ | An LTC6992 Pulse-Width Modulator allows the switching MOSFET' | ||
+ | \\ | ||
^ ^ Duty Cycle Source Selection | ^ ^ Duty Cycle Source Selection | ||
^ | ^ | ||
| | | | ||
| | | | ||
- | | ::: | + | | ::: |
- | | Notes | | + | | Notes | |
+ | \\ | ||
+ | \\ | ||
- | ==== Control Mode Selection ==== | ||
- | ^ ^ | ||
- | ^ | ||
- | | | ||
- | | | ||
- | | ::: | ||
- | | Notes | | ||
- | |||
- | |||
- | ==== FET Selection ==== | ||
- | ^ ^ FET Selection | ||
- | ^ | ||
- | | | ||
- | | | ||
- | | ::: | ||
- | |||
- | |||
- | ==== Current Sense Selection ==== | ||
- | ^ ^ | ||
- | ^ | ||
- | | | ||
- | | | ||
- | | ::: | ||
- | | Notes | | ||
- | |||
- | |||
- | ==== FET and Current Sense Selection ==== | ||
- | ^ ^ FET Selection | ||
- | ^ | ||
- | | | ||
- | | | ||
- | | ::: | ||
- | | Notes | | ||
==== Current Threshold Source Selection ==== | ==== Current Threshold Source Selection ==== | ||
+ | In peak-current control modes, the peak current can be controlled either manually by adjusting the CURRENT THRESHOLD knob or under the control of the error amplifier. The current threshold is also always active in voltage control modes, maintaining the per-cycle current limit as an added safety and robustness feature. | ||
+ | \\ | ||
^ ^ | ^ ^ | ||
^ | ^ | ||
| | | | ||
| | | | ||
- | | ::: | + | | ::: |
| Notes | **Set Duty Cycle pot to approx. 50%. (not critical, rising edge controls start of the ramp)** | | Notes | **Set Duty Cycle pot to approx. 50%. (not critical, rising edge controls start of the ramp)** | ||
+ | \\ | ||
+ | \\ | ||
+ | ==== Feedback Selection ==== | ||
+ | Three options for feedback network are provided, assuming a 1.25 V reference voltage. The 5V option is usually used for buck experiments (input voltage greater than 5 V), and the 12 V option is usually used for boost experiments (input less than 12 V). Footprints for optional 0603-sized resistors are included for user-defined feedback networks selected by the third jumper option. | ||
+ | \\ | ||
+ | ^ ^ | ||
+ | ^ | ||
+ | | | ||
+ | | | ||
+ | | ::: | ||
+ | \\ | ||
+ | \\ | ||
+ | ==== Signal Measurement and Injection Points ==== | ||
+ | The ADALM-SR1 provides numerous test points for stimulating (modulating) and measuring the operation of the circuit, such as input and output voltage, inductor current, and output current. Several aspects of the circuit' | ||
+ | \\ | ||
+ | * In open-loop voltage mode, modulate the duty cycle control voltage to characterize the response of the power stage | ||
+ | * In open-loop current mode, modulate the current threshold (ITH) to characterize the response of the power stage | ||
+ | * In any closed-loop mode, modulate the feedback divider to characterize the closed-loop response of the whole circuit. | ||
+ | \\ | ||
+ | Connections are summarized in Figure X below and the following tables. | ||
+ | \\ | ||
+ | {{ : | ||
+ | \\ | ||
- | ==== Measurement Points ==== | ||
^ | ^ | ||
^ ^ | ^ ^ | ||
| | | | ||
- | | ::: | ||
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- | | ::: | ||
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- | | ::: | + | | |
- | | | + | | |
- | | ::: | + | |
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- | | ::: | + | |
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- | | ::: | ||
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- | | ::: | ||
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- | | ::: | ||
| | | | ||
- | | ::: | ||
- | ==== Injection Points ==== | + | |
^ | ^ | ||
^ ^ | ^ ^ | ||
- | | | + | | |
- | | ::: | + | |
| | | | ||
- | | ::: | ||
| | | | ||
- | | ::: | + | |
===== Hardware Setup Procedure ===== | ===== Hardware Setup Procedure ===== | ||
- | Figure 2 shows the ADALM2000 (M2K) connections for measuring the switch node voltage on Channel 1 and ripple current on Channel 2. Connect all 4 of the M2K's ground leads and 1-, 2- leads to the row of 6 ground posts at the top of the board... | ||
- | |||
- | {{ : | ||
- | |||
- | <WRAP centeralign> | ||
+ | Refer to individual lab exercises for detailed setup information. | ||
===== Auxiliary Circuit Details ===== | ===== Auxiliary Circuit Details ===== | ||
- | The setup and operation of circuitry associated with the lab exercises | + | The setup and operation of circuitry associated with the lab exercises |
\\ | \\ | ||
- | + | {{ : | |
- | ==== Housekeeping supplies and reference ==== | + | |
- | The ADALM-SR1 has two power inputs. The experiment power input is supplied by the user, and the voltage will vary depending on the experiment being run. An additional micro USB connector is the input for a 5V " | + | |
- | + | ||
- | {{ : | + | |
\\ | \\ | ||
- | + | ==== Housekeeping Supplies and Reference ==== | |
- | An LT1970-1.25 provides an accurate reference for the error amplifier and duty cycle, current threshold adjustment potentiometers. | + | The ADALM-SR1 has two power inputs. The user supplies the experiment power input, and the voltage will vary depending on the experiment being run. An additional micro USB connector is the input for a 5 V " |
- | + | \\ | |
- | {{ : | + | \\ |
+ | An LT1970-1.25 provides an accurate reference for the error amplifier and duty cycle current threshold adjustment potentiometers. | ||
+ | \\ | ||
\\ | \\ | ||
==== Input Overvoltage, | ==== Input Overvoltage, | ||
- | An LTC4368 and associated circuitry protects the experiment power input by only turning on when the supply is between | + | The Figure below shows an LTspice schematic of the ADALM-SR1' |
- | + | \\ | |
- | {{ : | + | {{ : |
+ | \\ | ||
+ | An LTC4368 and associated circuitry protects the experiment power input by only turning on when the supply is between | ||
+ | \\ | ||
\\ | \\ | ||
==== Output Overvoltage ==== | ==== Output Overvoltage ==== | ||
- | In boost mode, the ADSRALM can produce high voltages under certain conditions: if the duty cycle is high and the load is light, or if feedback is disconnected. An LTC2912 overvoltage / undervoltage supervisor will disable the switching circuitry if the output exceeds | + | In boost mode, the ADSRALM can produce high voltages under certain conditions: if the duty cycle is high and the load is light, or if feedback is disconnected. An LTC2912 overvoltage / undervoltage supervisor will disable the switching circuitry if the output exceeds |
- | + | \\ | |
- | {{ : | + | |
\\ | \\ | ||
==== Inductor, Load Resistor Overtemperature ==== | ==== Inductor, Load Resistor Overtemperature ==== | ||
The inductor and onboard load resistors can get warm during certain experiments or if the board is misconfigured. Three temperature sensors measure the inductor temperature and the temperature of the high-dissipation areas of the load resistor bank. If any temperature exceeds 60ºC, switching is disabled for a 1.9 second cool-down period. | The inductor and onboard load resistors can get warm during certain experiments or if the board is misconfigured. Three temperature sensors measure the inductor temperature and the temperature of the high-dissipation areas of the load resistor bank. If any temperature exceeds 60ºC, switching is disabled for a 1.9 second cool-down period. | ||
- | + | \\ | |
- | The low-resistance loads consist of parallel, single 100Ω, 1/2W resistors | + | \\ |
- | + | The low-resistance loads consist of parallel, single 100 Ω, 1/2 W resistors. An orange LED near the associated jumpers illuminates when the output voltage exceeds | |
- | The high resistance loads consist of multiples of two 100-ohm, 1/2W resistors in series, which will handle voltages up to 14V. A temperature sensor is still included in case the output voltage exceeds | + | \\ |
- | + | \\ | |
- | {{ : | + | The high resistance loads consist of multiples of two 100-ohm, 1/4 W resistors in series, which will handle voltages up to 14 V. A temperature sensor is still included in case the output voltage exceeds |
\\ | \\ | ||
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<WRAP round 80% download> | <WRAP round 80% download> | ||
+ | ADALM-SR1 | ||
+ | * {{ : | ||
+ | </ | ||
- | SRALM-EBZ | + | ===== Corner Case Test Report ===== |
- | (PLACEHOLDERS) | + | |
- | * {{ : | + | |
- | * {{ : | + | |
- | * {{ : | + | |
- | * {{ : | + | |
+ | <WRAP round 80% download> | ||
+ | This is an informal internal test report intended to exercise operating conditions outside those detailed in the experiments. This may be useful for those developing additional exercises.\\ | ||
+ | * {{ : | ||
</ | </ | ||
+ | <WRAP important> | ||
//End of Document// | //End of Document// |