ServoStation
A ServoStation: it's kind of like a BEC,
but a whole lot better in so many ways.
A ServoStation is basically a power supply for your servos, on steroids. A ServoStation eliminates the need for a servo battery, and operates from virtually any 8 - 22 volt power source.
You plug up to 8 servos into the ServoStation, and it feeds them with all the voltage and current they need. 30 Watts of it, in fact. But that's just the beginning. The ServoStation also feeds 5 volts back up the inbound servo cables to power your radio receiver or autopilot. Or Failsafe Device. Or microcontroller board. Or indeed anything at all that needs 5 volts.
Plus the ServoStation internally buffers all the PWM signals. That's right, 8 servo pulse amplifiers with very beefy output stages.
And there's lots more:
- Our switching power supply is up to 95% efficient at 5 Amps. Nothing else comes close.
- Conservatively rated to 5 Amps continuous, and 7.5 Amps peak.
- Ultra-quiet receiver power supply - typically less than 20mVp-p noise.
- Fully reverse-polarity protected, and protects everything it powers.
- Operates over the full industrial temperature range (-40 to +85° Celsius).
- Solves the 3 Amp connector limit problem whilst continuing to use the industry-standard 3-pin servo connector.
- Can have a mix of 5 and 6 volt devices simultaneously.
- An engineering datasheet. Hard to believe, we know, but it's true.
- Rugged aluminium enclosure also provides low EMI.
- Graceful and predictable behaviour with a failing battery.
We reckon than anything a BEC can do, a ServoStation can do better. Read on for a more detailed look at some of the ServoStation's main features.
Efficiency
A ServoStation has a worst-case efficiency of 90% at 1 Amp.
But at 1 Amp it's barely ticking over.
As the output current rises so does the efficiency. At 3 Amps the efficiency is up to 94%, and at 5 Amps the efficiency can be as high as 95%.
The connector limit problem
This is how most BECs are wired up.
That servo cable connector feeding the receiver (and thus all the servos) is rated to 3 Amps.
That's a bit of a problem.
Not only is that connection an obvious point of failure, it also means that no matter how many Amps your BEC can generate, only 3 of them can get through.
The ServoStation solution
This is how a ServoStation is wired up.
Note the redundant connections to the receiver, reducing the probability of failure.
That 3 Amp connector limit has gone, now it's 3 Amps per servo, the way it's supposed to be.
The servos are running off a high efficiency, high current 6 volt rail, and the receiver is running off a separate low noise 5 volt rail. Servo and switching noise on the 6 volt rail is filtered out by the ServoStation, leaving the receiver to get on with its job of receiving tiny signals in relative peace and quiet.
Servo Pulse Amplifiers
Inside the ServoStation are 8 servo pulse amplifiers, which clean-up and then beef-up the servo control signals. These devices are variously known as "servo boosters", "servo pulse boosters", and even "servo boost amplifiers". There are several good reasons why they are important:
- Signal integrity: The servo control signals generated by many receivers are sub-optimal in terms of amplitude and drive capability. The ServoStation fixes these problems by squaring up the signals and then running them through low-impedance output drivers. This means the ServoStation can drive long cable runs out to distant servos, or multiple servos per output.
- Electrical isolation between the receiver and servos is maximised. Any servo noise injected onto the control lines can no longer reach the receiver and degrade its RF sensitivity. And because the receiver is running off its own dedicated 5 volt rail, the only signal which remains common to the receiver and servos is ground.
- Voltage conversion: Not all 3.3V, 3.0V and 2.7V devices can drive servos reliably. The servo pulse amplifiers convert these low voltage signals to more servo compatible levels.
