Вопрос о pdoTools и where

$pdo = $modx->getService('pdoFetch');

$collection = $pdo->getCollection('modResource',
            array('template' => 5, 'published' => 1),
            array(
            'parents' => 28,
            'sortbyTV' => 'event_date_time',
            'includeTVs' => 'event_date_time,event_place',
            'sortbyTVType' => 'datetime',
            'sortdirTV' => 'ASC',
            'where' => '{"event_place":"Берлога"}'  // Волшебство не получилось
            )
);

foreach ($collection as $key)
{
  // То-сё, пятое, десятое;
}

'where' => '{"event_place":"Берлога"}'